USN-8651-1: curl vulnerability

unknownCVE-2026-11856

It was discovered that curl incorrectly handled reusing connections when the origin changed between transfers. A remote attacker could possibly use this issue to obtain sensitive information.

CSIRTS triage

vendor: curl product: curl Information disclosure

What: curl incorrectly reuses connections when origin changes between transfers, permitting information disclosure.
Who is affected: curl users performing sequential transfers with origin changes.
Urgency: Unknown; requires assessment of exploitation likelihood in typical deployment patterns.
Action: Update curl to patched version when available; monitor curl security advisories for CVE-2026-11856 details.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Ubuntu Security Notices (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-08-19
Exploitation: Not in CISA KEV at last sync

Original advisory: https://ubuntu.com/security/notices/USN-8651-1

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-118560.60% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 46% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-11856	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[UPDATE] [medium] cURL: Multiple vulnerabilitiescert-bund
unknownMultiple vulnerabilities in Tenable Security Center (August 14, 2026)cert-fr-avis
mediumCVE-2026-11856: cross-origin Digest auth state leakmsrc
criticalCVE-2026-11856: Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest*…nvd
unknownMultiple vulnerabilities in cURL and libcurl (June 24, 2026)cert-fr-avis