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Full vulnerability report · 2025
CVE-2025-55753High confidence

Apache HTTP Server: mod_md (ACME), unintended retry intervals

Apache Software Foundation · Apache HTTP Server

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.45% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Apache Software Foundation Apache HTTP Server and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

8 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · mainapache2Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.4.66-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.22v3.22 · mainapache2Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.4.66-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.21v3.21 · mainapache2Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.2.4.66-r0Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourceapache2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.66-1~deb13u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourceapache2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.66-1~deb12u1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourceapache2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.66-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourceapache2Vendor fix publishedDebian records a fixed source-package version for this release.2.4.66-1Debian Security Tracker ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · standard archiveapache2Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.2.4.58-1ubuntu8.10Canonical Ubuntu Security ↗Source updated 5 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current
CVE-2025-55753 · CSAF 2.0 · revision 33 · interimSUSE Product Security TeamCVE-2025-55753
127 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • apache2 as component of SLES-LTSS-TERADATA 15 SP2
  • apache2 as component of SUSE Linux Enterprise Desktop 15 SP6
  • apache2 as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2-doc as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2-prefork as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2-utils as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2-worker as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • apache2 as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • apache2-devel as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • apache2-doc as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • apache2-prefork as component of SUSE Linux Enterprise High Performance Computing 15 SP2
Summary
An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2025-55753 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitymod_md: Apache HTTP Server: mod_md (ACME), unintended retry intervals
462 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • jbcs-httpd24-mod_md-1:2.4.28-13.el7jbcs.src as a component of Red Hat JBoss Core Services on RHEL 7 Server
  • jbcs-httpd24-mod_md-1:2.4.28-13.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
  • jbcs-httpd24-mod_md-debuginfo-1:2.4.28-13.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
  • jbcs-httpd24-mod_md-1:2.4.28-13.el8jbcs.src as a component of Red Hat JBoss Core Services on RHEL 8
  • jbcs-httpd24-mod_md-1:2.4.28-13.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
  • jbcs-httpd24-mod_md-debuginfo-1:2.4.28-13.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
  • mod_md-1:2.4.26-3.el10_0.1.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • mod_md-1:2.4.26-3.el10_0.1.ppc64le as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • mod_md-1:2.4.26-3.el10_0.1.s390x as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • mod_md-1:2.4.26-3.el10_0.1.src as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • mod_md-1:2.4.26-3.el10_0.1.x86_64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
  • mod_md-debuginfo-1:2.4.26-3.el10_0.1.aarch64 as a component of Red Hat Enterprise Linux AppStream EUS (v. 10.0)
Summary
An integer overflow flaw has been discovered in the Apache HTTP server. The integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-201395

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.

What

An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.

Why

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. This issue affects Apache HTTP Server: from 2.4.30 before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.

Why

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Integer Overflow or Wraparound → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-190 ↗

CWE-190: Integer Overflow or Wraparound. The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-190
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2026-2189Dell PowerProtect Data Domain: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Dell PowerProtect Data Domain ausnutzen, um seine Privilegien zu erhöhen um beliebigen Programmcode auszuführen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um einen Cross-Site Scripting Angriff durchzuführen, um Informationen offenzulegen, und um Dateien zu manipulieren.

Official advisory ↗
BSI · German · WID-SEC-2026-0853Apple macOS: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Apple macOS ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, und um seine Privilegien zu erhöhen.

Official advisory ↗
BSI · German · WID-SEC-2026-0349Dell Avamar und NetWorker: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Dell Avamar und Dell NetWorker ausnutzen, um Angriffe zu starten, die die Integrität, Vertraulichkeit und Verfügbarkeit von Systemen beeinträchtigen.

Official advisory ↗
BSI · German · WID-SEC-2025-2750Apache HTTP Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Apache HTTP Server ausnutzen, um beliebigen Programmcode auszuführen, um Informationen offenzulegen, und um Sicherheitsvorkehrungen zu umgehen.

Official advisory ↗
BSI · German · WID-SEC-2026-1730Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Ein Angreifer kann mehrere Schwachstellen in Xerox FreeFlow Print Server ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20251210Security Bulletin 10 Dec 2025

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Dec 2025, published on 10 December 2025. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0355Multiples vulnérabilités dans les produits Apple

mars 2026 https://support.apple.com/en-us/126797 Bulletin de sécurité Apple 126798 du 24 mars 2026 https://support.apple.com/en-us/126798 Bulletin de sécurité Apple 126799 du 24 mars 2026 https://support.apple.com/en-us/126799 Bulletin de sécurité Apple 126800 du 24 mars 2026 https://support.apple.com/en-us/126800 Bulletin de sécurité Apple 126801 du 24 mars 2026 https://support.apple.com/en-us/126801 Référence CVE CVE-2025-14524 https://www.cve.org/CVERecord?id=CVE-2025-14524 Référence CVE CVE-2025-43376 https://www.cve.org/CVERecord?id=CVE-2025-43376 Référence CVE CVE-2025-43534 https://www.cve.org/CVERecord?id=CVE-2025-43534 Référence CVE CVE-2025-55753 https://www.cve.org/CVERecord?id=CVE-2025-55753 Référence CVE CVE-2025-58098 https://www.cve.org/CVERecord?id=CVE-2025-58098 Référence CVE CVE-2025-59775 https://www.cve.org/CVERecord?id=CVE-2025-59775 Référence CVE CVE-2025-64505 https://www.cve.org/CVERecord?id=CVE-2025-64505 Référence CVE CVE-2025-65082 https://www.cve.org/CVERecord?id=CVE-2025-65082 Référence CVE CVE-2025-66200 https://www.cve.org/CVERecord?id=CVE-2025-66200 Référence CVE CVE-2026-20607 https://www.cve.org/CVERecord?id=CVE-2026-20607 Référence CVE CVE-2026-20631 https://www.cve.org/CVERecord?id=CVE-2026-20631 Référence CVE CVE-2026-20632 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0199Multiples vulnérabilités dans les produits VMware

rd?id=CVE-2025-5025 Référence CVE CVE-2025-52565 https://www.cve.org/CVERecord?id=CVE-2025-52565 Référence CVE CVE-2025-52881 https://www.cve.org/CVERecord?id=CVE-2025-52881 Référence CVE CVE-2025-52999 https://www.cve.org/CVERecord?id=CVE-2025-52999 Référence CVE CVE-2025-53057 https://www.cve.org/CVERecord?id=CVE-2025-53057 Référence CVE CVE-2025-53066 https://www.cve.org/CVERecord?id=CVE-2025-53066 Référence CVE CVE-2025-54410 https://www.cve.org/CVERecord?id=CVE-2025-54410 Référence CVE CVE-2025-55163 https://www.cve.org/CVERecord?id=CVE-2025-55163 Référence CVE CVE-2025-55752 https://www.cve.org/CVERecord?id=CVE-2025-55752 Référence CVE CVE-2025-55753 https://www.cve.org/CVERecord?id=CVE-2025-55753 Référence CVE CVE-2025-58056 https://www.cve.org/CVERecord?id=CVE-2025-58056 Référence CVE CVE-2025-58057 https://www.cve.org/CVERecord?id=CVE-2025-58057 Référence CVE CVE-2025-58058 https://www.cve.org/CVERecord?id=CVE-2025-58058 Référence CVE CVE-2025-58098 https://www.cve.org/CVERecord?id=CVE-2025-58098 Référence CVE CVE-2025-58181 https://www.cve.org/CVERecord?id=CVE-2025-58181 Référence CVE CVE-2025-58183 https://www.cve.org/CVERecord?id=CVE-2025-58183 Référence CVE CVE-2025-58185 https://www.cve.org/CVERecord?id=CVE-2025-58185 Référence CVE CVE-2025-58186 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-1071Multiples vulnérabilités dans Apache HTTP Server

De multiples vulnérabilités ont été découvertes dans Apache HTTP Server. Certaines d'entre elles permettent à un attaquant de provoquer une atteinte à la confidentialité des données, une falsification de requêtes côté serveur (SSRF) et un contournement de la politique de sécurité.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-021621整数オーバーフローによりApache HTTP ServerのACME証明書更新処理でバックオフタイマーが0になり更新試行が繰り返される脆弱性

ACME証明書の更新に失敗した際、整数オーバーフローが発生してデフォルト設定の場合約30日後にバックオフタイマーが0になります。その結果、証明書の更新試行が遅延なく繰り返され、成功するまで継続されます。本脆弱性は2.4.30から2.4.66未満のApache HTTP Serverに影響を及ぼします。対策として、2.4.66へのアップグレードを推奨します。

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0102Kwetsbaarheden verholpen in Apple macOS

Multiple vulnerabilities affect Oracle Communications Unified Assurance and Apache HTTP Server, including critical data compromise, denial of service, and issues in mod_md (ACME) components across various versions.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Action
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles1 stored document

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

  • About the security content of macOS Tahoe 26.4 - Apple Support →Original publisher ↗Searchable text snapshot · Captured 29 Sep 2026Apple Store Mac iPad iPhone Watch Vision AirPods TV & Home Entertainment Accessories Support 0 + "},{"name":"compact","assetInline":" "}],"analyticsAttributes":[{"name":"data-analytics-title","value":"apple home"}]},{"id":"ad4a2a26eb4836393385e9f6c61b526b4a3cb31409c5ed8730ce7a704dd7132f","name":"store","te
04

Evidence and provenance

Published 5 Dec 2025 · Last source change 5 Dec 2025, 19:27 UTC · CWE-190 · Integer Overflow or Wraparound

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-201395
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    2.4.30 < 2.4.66 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    2.4.30 < 2.4.66 · Fixed: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
    Red Hat Product Security ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2025-201395↗Vendor CSAF · SUSE Product Security Team↗Red Hat Product Security security advisory↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-55753 · cve.blacktree.nl