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Full vulnerability report · 2026
CVE-2026-11586High confidence

WS Auto-PONG memory exhaustion

curl · curl

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 15 Sep 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.61% 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.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs curl curl 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 3 daysRemediation target: Within 90 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 findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 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 · maincurlVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.8.22.0-r0Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourcecurlNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcecurlNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcecurlVendor fix publishedDebian records a fixed source-package version for this release.8.21.0~rc3-1Debian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcecurlVendor fix publishedDebian records a fixed source-package version for this release.8.21.0~rc3-1Debian Security Tracker ↗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-2026-11586 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitycurl: curl: Denial of Service via WebSocket PING flood
8 known affected

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

  • curl as a component of Red Hat Enterprise Linux 6
  • curl.src as a component of Red Hat Enterprise Linux 6
  • libcurl as a component of Red Hat Enterprise Linux 6
  • libcurl-devel as a component of Red Hat Enterprise Linux 6
  • curl as a component of Red Hat Enterprise Linux 7
  • curl.src as a component of Red Hat Enterprise Linux 7
  • libcurl as a component of Red Hat Enterprise Linux 7
  • libcurl-devel as a component of Red Hat Enterprise Linux 7
Summary
A flaw was found in curl. A malicious server can exploit this vulnerability by sending rapid, sequential WebSocket PING messages. Due to a lack of an upper bound on memory allocation for unacknowledged frames, curl can be forced to exhaust all available memory, leading to a denial of service.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
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-2026-41500

No EUVD known-exploited evidence

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

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
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

What

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Allocation of Resources Without Limits or Throttling → 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-770 ↗

CWE-770: Allocation of Resources Without Limits or Throttling. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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:N/I:N/A:H

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.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
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-770Public exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-41500Official EUVD mapping

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

Official EUVD record ↗
BSI · German · WID-SEC-2026-2052cURL: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in cURL ausnutzen, um Sicherheitsvorkehrungen zu umgehen, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand oder eine Speicherbeschädigung zu verursachen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260708Security Bulletin 8 July 2026 [PDF, 1MB]]

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 8 July 2026 [PDF, 1MB]], published on 8 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1023Multiples vulnérabilités dans Tenable Security Center

De multiples vulnérabilités ont été découvertes dans Tenable Security Center. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, une élévation de privilèges et une injection SQL (SQLi).

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0797Multiples vulnérabilités dans cURL et libcurl

S des bulletins d'actualité Premier Ministre S.G.D.S.N Agence nationale de la sécurité des systèmes d'information Paris, le 24 juin 2026 N° CERTFR-2026-AVI-0797 Affaire suivie par: CERT-FR Avis du CERT-FR Objet: Multiples vulnérabilités dans cURL et libcurl Gestion du document Référence CERTFR-2026-AVI-0797 Titre Multiples vulnérabilités dans cURL et libcurl Date de la première version 24 juin 2026 Date de la dernière version 24 juin 2026 Source(s) Bulletin de sécurité Curl CVE-2026-10536 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-11352 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-11564 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-11586 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-11856 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-12064 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8286 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8458 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8924 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8925 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8926 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8927 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-8932 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-9079 du 24 juin 2026 Bulletin de sécurité Curl CVE-2026-9080 du 24 juin 2026 Bulletin de séc

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-022726HaxxのcURLにおける制限またはスロットリング無しのリソースの割り当てに関する脆弱性

デフォルトでは、curlはWebSocketのPINGフレームに自動的に応答します。curlは未確認のフレームに対するメモリ割り当ての上限を持っていないため、悪意のあるサーバーは急速かつ連続したPINGメッセージをcurlに洪水のように送りつけることで、利用可能なメモリをすべて使い果たす可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6865curl 제품 보안 업데이트 권고

curl에서 발생하는 Allocation of Resources Without Limits or Throttling 취약점(CVE-2026-11586) [16] libcurl에서 발생하는 Allocation of Resources Without Limits or Throttling 취약점(CVE-2026-11586) [16]

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
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
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 3 Jul 2026 · Last source change 15 Sept 2026, 06:02 UTC · CWE-770 · Allocation of Resources Without Limits or Throttling

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-2026-41500
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

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
    8.20.0 ≤ 8.20.0; 8.19.0 ≤ 8.19.0; 8.18.0 ≤ 8.18.0; 8.17.0 ≤ 8.17.0; 8.16.0 ≤ 8.16.0 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    curl: 8.16.0 < 8.16.1, 8.17.0 < 8.20.1, 0b091328773c64e23f5c4739da74527093c6a5ab < 849317ff5c5a5e13f50ec3d001e46ddffa77d8a4, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    curl: 8.16.0 < 8.16.1, 8.17.0 < 8.20.1, 0b091328773c64e23f5c4739da74527093c6a5ab < 849317ff5c5a5e13f50ec3d001e46ddffa77d8a4, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    curl: 8.16.0 < 8.16.1, 8.17.0 < 8.20.1, 0b091328773c64e23f5c4739da74527093c6a5ab < 849317ff5c5a5e13f50ec3d001e46ddffa77d8a4, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0 · Fixed: For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
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-2026-11586 · cve.blacktree.nl