libcurl wolfSSL CA Caching Bypass via CURLOPT_SSL_CTX_FUNCTION
CVE-2026-82208 Published on September 6, 2026
wolfSSL CA-cache hit overrides callback
With the wolfSSL backend, when CA caching is enabled and an
`CURLOPT_SSL_CTX_FUNCTION` callback replaces the trust store, libcurl can
silently reinstall the cached store after the callback returns. A certificate
trusted by the cached store but rejected by the callback-selected store is
then incorrectly accepted.
Vulnerability Analysis
CVE-2026-82208 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and 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-2026-82208
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Affected Versions
curl:- Version 8.9.1 and below 8.14.2 is affected.
- Version 8.15.0 and below 8.16.1 is affected.
- Version 8.17.0 and below 8.20.1 is affected.
- Version 8.21.0 and below 8.22.0 is affected.
- Version 0f2876b2c33f6784a27b6f7345bd8cd95b46352a and below ed0338befd1d865a8ea1fbaa90013a096dedd07a is affected.
- Version 8.21.0 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.
- Version 8.16.0 is affected.
- Version 8.15.0 is affected.
- Version 8.14.1 is affected.
- Version 8.14.0 is affected.
- Version 8.13.0 is affected.
- Version 8.12.1 is affected.
- Version 8.12.0 is affected.
- Version 8.11.1 is affected.
- Version 8.11.0 is affected.
- Version 8.10.1 is affected.
- Version 8.10.0 is affected.
- Version 8.9.1 is affected.