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Full vulnerability report · 2025
CVE-2025-23419High confidence

TLS Session Resumption Vulnerability

F5 · NGINX Open Source

Official source article: F5 K000149173 ↗. Check the applicable product and release in the original source.

5.3MediumCVSS 4.0
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 2.79% 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 F5 NGINX Open Source 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: As exposure requiresRemediation target: Within 365 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 · mainnginxVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.1.26.3-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.22v3.22 · mainnginxVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.1.26.3-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.21v3.21 · mainnginxVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.1.26.3-r0Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourcenginxVendor fix publishedDebian records a fixed source-package version for this release.1.26.3-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcenginxVendor fix publishedDebian records a fixed source-package version for this release.1.22.1-9+deb12u1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcenginxVendor fix publishedDebian records a fixed source-package version for this release.1.26.3-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcenginxVendor fix publishedDebian records a fixed source-package version for this release.1.26.3-2Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivenginxVendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.1.24.0-2ubuntu7.3Canonical 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.

1 current
CVE-2025-23419 · CSAF 2.0 · revision 28 · interimSUSE Product Security TeamCVE-2025-23419
70 known affected

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

  • nginx as component of SLES-LTSS-TERADATA 15 SP2
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • nginx-source as component of SUSE Linux Enterprise High Performance Computing 15 SP1
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • nginx-source as component of SUSE Linux Enterprise High Performance Computing 15 SP2
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS
  • nginx-source as component of SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • nginx-source as component of SUSE Linux Enterprise High Performance Computing 15 SP3
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • nginx-source as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • nginx as component of SUSE Linux Enterprise High Performance Computing 15 SP4
Summary
When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
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-2025-3168

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 actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication.   Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

What

When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication.   Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication.   Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Why

The application performs an authorisation check, but it does not correctly enforce the required permission boundary.

How

An attacker operating through a network path may attempt exploitation with low privileges. 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 → Incorrect Authorization → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-863 ↗

CWE-863: Incorrect Authorization. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: 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.ATNoneAttack requirements: No additional deployment or execution condition is required.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCLowVulnerable-system confidentiality: A successful attack can cause a limited loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: 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.
NetworkCWE-863
A

Official authority intelligence

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

BSI · German · WID-SEC-2025-0287F5 BIG-IP: Mehrere Schwachstellen

Ein Angreifer kann diese Schwachstellen ausnutzen, um beliebige Systembefehle auszuführen, Sicherheitsmaßnahmen zu umgehen, Cross-Site-Scripting-Angriffe durchzuführen und einen Denial-of-Service-Zustand zu erzeugen.

Official advisory ↗
BSI · German · WID-SEC-2025-0274NGINX: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen

Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in NGINX NGINX Plus und NGINX ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20250206Security Bulletin 6 Feb 2025

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 6 Feb 2025, published on 6 February 2025. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0112Multiples vulnérabilités dans les produits VMware

d?id=CVE-2025-22228 Référence CVE CVE-2025-22233 https://www.cve.org/CVERecord?id=CVE-2025-22233 Référence CVE CVE-2025-22235 https://www.cve.org/CVERecord?id=CVE-2025-22235 Référence CVE CVE-2025-22868 https://www.cve.org/CVERecord?id=CVE-2025-22868 Référence CVE CVE-2025-22869 https://www.cve.org/CVERecord?id=CVE-2025-22869 Référence CVE CVE-2025-22870 https://www.cve.org/CVERecord?id=CVE-2025-22870 Référence CVE CVE-2025-22871 https://www.cve.org/CVERecord?id=CVE-2025-22871 Référence CVE CVE-2025-22872 https://www.cve.org/CVERecord?id=CVE-2025-22872 Référence CVE CVE-2025-22874 https://www.cve.org/CVERecord?id=CVE-2025-22874 Référence CVE CVE-2025-23419 https://www.cve.org/CVERecord?id=CVE-2025-23419 Référence CVE CVE-2025-28162 https://www.cve.org/CVERecord?id=CVE-2025-28162 Référence CVE CVE-2025-28164 https://www.cve.org/CVERecord?id=CVE-2025-28164 Référence CVE CVE-2025-31133 https://www.cve.org/CVERecord?id=CVE-2025-31133 Référence CVE CVE-2025-3360 https://www.cve.org/CVERecord?id=CVE-2025-3360 Référence CVE CVE-2025-39964 https://www.cve.org/CVERecord?id=CVE-2025-39964 Référence CVE CVE-2025-39993 https://www.cve.org/CVERecord?id=CVE-2025-39993 Référence CVE CVE-2025-40018 https://www.cve.org/CVERecord?id=CVE-2025-40018 Référence CVE CVE-2025-41242 https://www.cve.org/CVERecord?id=CV

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0109Vulnérabilité dans Nginx

Une vulnérabilité a été découverte dans Nginx. Elle permet à un attaquant de provoquer un contournement de la politique de sécurité.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0099Multiples vulnérabilités dans les produits F5

De multiples vulnérabilités ont été découvertes dans les produits F5. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2025-019247F5 Networks の nginx 等複数ベンダの製品におけるセッション期限に関する脆弱性

F5 Networks の nginx 等複数ベンダの製品には、セッション期限に関する脆弱性が存在します。

Official advisory ↗
NCSC-NL · Dutch · NCSC-2025-0041Kwetsbaarheden verholpen in F5 BIG-IP

Een kwaadwillende kan de kwetsbaarheden misbruiken om aanvallen uit te voeren die kunnen leiden tot de volgende categorieën schade: - Denial-of-Service (DoS) - Omzeilen van een beveiligingsmaatregel - Uitvoer van willekeurige code (Root/admin) - Uitvoer van willekeurige code (Gebruiker) - Toegang tot gevoelige gegevens

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
No fixed version is explicitly recorded in the structured CVE data.
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.
04

Evidence and provenance

Published 5 Feb 2025 · Last source change 23 Jan 2026, 20:09 UTC · CWE-863 · Incorrect Authorization

CVE recordCVE.org · 5.2
CVSS sourceCNA
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-2025-3168
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. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    SUSE Product Security Team ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2025-3168↗SUSE Product Security Team security advisory↗CVE authority or vendor reference · F5 K000149173↗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-2025-23419 · cve.blacktree.nl