libcurl CA Trust Leakage via Persistent Connection Pool
CVE-2026-11564 Published on July 3, 2026
Native CA trust persist
libcurl keeps previously used connections in a connection pool for subsequent
transfers to reuse if one of them matches the setup.
An easy handle that first uses default native CA trust can continue trusting
the native platform store after the application switches that same handle to
custom CA material for a later transfer.
Vulnerability Analysis
CVE-2026-11564 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-11564. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Improper Certificate Validation
The software does not validate, or incorrectly validates, a certificate. When a certificate is invalid or malicious, it might allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. The software might connect to a malicious host while believing it is a trusted host, or the software might be deceived into accepting spoofed data that appears to originate from a trusted host.
Products Associated with CVE-2026-11564
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Affected Versions
curl:- Version 8.17.0 and below 8.20.1 is affected.
- Version eefd03c572996e5de4dec4fe295ad6f103e0eefc and below d69bfad3fa3daf5e72331f6870667607828d5891 is affected.
- Version 8.20.0 is affected.
- Version 8.19.0 is affected.
- Version 8.18.0 is affected.
- Version 8.17.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.