CVE-2026-87866
Critical
Description
When built with wolfSSL, curl can successfully validate a pinned public key hash against a key the TLS peer does not possess. During the TLS handshake, wolfSSL validates the connection, but curl's subsequent re-parsing of the same certificate - tricked by a manipulated validity length field - extracts and matches a different embedded key, incorrectly authorizing the pinned public key.
SeverityCritical
CVSS9.1
Exploit probability—
ProductCurl
PublishedOct 20, 2026
First seenOct 20, 2026
Weakness typeCWE-295CWE-295
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| curl curl | 8.22.0, 8.21.0, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1, 8.11.0, 8.10.1, 8.10.0, 8.9.1, 8.9.0, 8.8.0, 8.7.1, 8.7.0, 8.6.0, 8.5.0, 8.4.0, 8.3.0, 8.2.1, 8.2.0, 8.1.2, 8.1.1, 8.1.0, 8.0.1, 8.0.0, 7.88.1, 7.88.0, 7.87.0, 7.86.0, 7.85.0, 7.84.0, 7.83.1, 7.83.0, 7.82.0, 7.81.0, 7.80.0, 7.79.1, 7.79.0, 7.78.0, 7.77.0, 7.76.1, 7.76.0, 7.75.0, 7.74.0, 7.73.0, 7.72.0, 7.71.1, 7.71.0, 7.70.0, 7.69.1, 7.69.0, 7.68.0, 7.67.0, 7.66.0, 7.65.3, 7.65.2, 7.65.1, 7.65.0, 7.64.1, 7.64.0, 7.63.0, 7.62.0, 7.61.1, 7.61.0, 7.60.0, 7.59.0, 7.58.0, 7.57.0, 7.56.1, 7.56.0, 7.55.1, 7.55.0, 7.54.1, 7.54.0, 7.53.1, 7.53.0, 7.52.1, 7.52.0, 7.51.0, 7.50.3, 7.50.2, 7.50.1, 7.50.0, 7.49.1, 7.49.0, 7.48.0, 7.47.1, 7.47.0, 7.46.0, 7.45.0, 7.44.0, 7.43.0 | — |
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