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libcurl CVE-2026-8932

| EUVDEUVD-2026-41509 HIGH
7.5
CVSS 3.1 · Vendor
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Severity by source

Vendor (CNA) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
vuln.today AI
5.9 MEDIUM

Integrity-only impact from using the wrong mTLS identity (I:H, C:N/A:N); AC:H because it needs the specific handle-reuse-with-changed-client-cert pattern, with no attacker privileges or interaction required.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
SUSE
7.4 HIGH
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Red Hat
7.5 HIGH
qualitative

Primary rating from Vendor (CNA).

CVSS VectorVendor

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

Lifecycle Timeline

7
Analysis Updated
Jul 06, 2026 - 18:48 vuln.today
v5 (cvss_changed)
Analysis Updated
Jul 06, 2026 - 18:47 vuln.today
v4 (cvss_changed)
Analysis Updated
Jul 06, 2026 - 18:45 vuln.today
v3 (cvss_changed)
Analysis Updated
Jul 06, 2026 - 18:45 vuln.today
v2 (cvss_changed)
Re-analysis Queued
Jul 06, 2026 - 18:22 vuln.today
cvss_changed
CVSS changed
Jul 06, 2026 - 18:22 NVD
7.5 (HIGH)
Analysis Generated
Jun 24, 2026 - 18:23 vuln.today

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

AnalysisAI

Incorrect mTLS connection reuse in libcurl (curl releases through 8.16.0) causes the library to reuse a pooled TLS connection even after client-certificate options - notably the private key - were changed in a way that should have forced a fresh handshake. Because those client-certificate settings were omitted from the connection-match logic, a later transfer can be sent over a connection authenticated with the wrong client identity, an integrity failure tagged as information disclosure. Rated CVSS 7.5 (C:N/I:H/A:N); EPSS is only 0.13% and there is no public exploit identified at time of analysis, though a HackerOne report (#3733910) drove the private disclosure.

Technical ContextAI

The flaw lives in libcurl's connection-pool reuse mechanism. libcurl keeps established connections in a pool so subsequent transfers on the same easy/multi handle can skip the TCP and TLS handshakes, gated by a configuration-match check that compares the security-relevant transfer settings. This vulnerability is a match-check omission: several TLS client-certificate options - specifically those governing the private key (the SSL key/cert file or blob and related mTLS settings such as CURLOPT_SSLKEY / CURLOPT_SSLCERT and their derivatives) - were not included in the comparison, so two setups differing only in their mTLS client credentials are treated as identical and the older connection is reused. No CWE is assigned in the input, but the root cause is an incomplete comparison of security-relevant state (an incorrect-comparison weakness, akin to CWE-697) leading to use of a connection carrying an unintended authentication context. No CPE strings were provided in the input, so exact product matching should be taken from the NVD/curl JSON.

RemediationAI

Upgrade libcurl to the fixed release announced in the curl project advisory at https://curl.se/docs/CVE-2026-8932.html; the provided input does not contain the exact patched version string, so treat the curl.se advisory and its JSON as the source of truth for the fixed version rather than an invented number - Patch available per vendor advisory, released patched version not independently confirmed from the provided data. As a compensating control until you can upgrade, avoid reusing the same libcurl easy/multi handle across transfers that use different client certificates or private keys, and instead use a fresh handle (or a separate connection cache) per client-certificate identity, which forces a clean handshake at the cost of losing connection-reuse performance. Applications that never change mTLS client-certificate options at runtime are effectively unaffected. Additional context is in the oss-security post at https://seclists.org/oss-sec/2026/q2/1012.

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Vendor StatusVendor

SUSE

Severity: Important
Product Status
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SLES15-SP6-CHOST-BYOS-Azure Affected
SLES15-SP6-CHOST-BYOS-EC2 Affected

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CVE-2026-8932 vulnerability details – vuln.today

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