Is CVE-2026-82208 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-82208 being exploited in the wild.

How severe is CVE-2026-82208?

High severity, with a CVSS score of 7.5, published 6 September 2026.

Which products and versions are affected?

curl libcurl 8.9.1 to 8.14.1, 8.15.0 to 8.16.0, 8.17.0 to 8.20.0, 8.21.0.

Is there a fix for CVE-2026-82208?

A patch was published on 2026-09-02: curl 8.22.0 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-82208 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-82208?

Check whether you run Haxx Curl. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-82208: curl libcurl certificate validation bypass in wolfSSL backend

CVE-2026-82208 · Severity: high · CVSS 7.5 · Published 2026-09-06

libcurl is a widely-used open-source library for transferring data over HTTP and HTTPS. When built with the wolfSSL TLS backend, a flaw in certificate caching can cause libcurl to accept certificates that should have been rejected by custom validation logic. An attacker with a certificate trusted by the system but explicitly rejected by an application's security policy could use this to perform man-in-the-middle attacks or impersonate trusted services.

Technologies: Haxx Curl. Vendors: Haxx.

Quick answers

Is CVE-2026-82208 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-82208 being exploited in the wild.
How severe is CVE-2026-82208?: High severity, with a CVSS score of 7.5, published 6 September 2026.
Which products and versions are affected?: curl libcurl 8.9.1 to 8.14.1, 8.15.0 to 8.16.0, 8.17.0 to 8.20.0, 8.21.0.
Is there a fix for CVE-2026-82208?: A patch was published on 2026-09-02: curl 8.22.0 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-82208 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-82208?: Check whether you run Haxx Curl. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

This vulnerability is an improper certificate validation flaw (CWE-295) affecting libcurl's wolfSSL backend. When CA caching is enabled and an application provides a CURLOPT_SSL_CTX_FUNCTION callback to customize the trust store, libcurl incorrectly reinstalls the cached certificate store after the callback returns, overriding the callback's certificate validation decisions. This allows a certificate that the callback rejected but the cached store trusts to be silently accepted. The attack requires the application to use both CA caching and CURLOPT_SSL_CTX_FUNCTION callbacks with wolfSSL; the curl command-line tool is not affected. Patches were released in curl versions 8.14.2, 8.16.1, 8.20.1, and 8.22.0.

Affected products

curl libcurl 8.9.1 to 8.14.1, 8.15.0 to 8.16.0, 8.17.0 to 8.20.0, 8.21.0

Timeline

2026-09-02: disclosed: Advisory published
2026-09-02: patched: curl 8.22.0 released with fix

References

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