CVE-2026-87866

Published: Oct 20, 2026Modified: Oct 29, 2026

9.1

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitability: 3.9 / Impact: 5.2

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Related CWEs

CWE-295

Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate.

References (4)

https://curl.se/docs/CVE-2026-87866.html

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

https://curl.se/docs/CVE-2026-87866.json

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

https://hackerone.com/reports/3989514

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

https://hackerone.com/reports/3989514

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Timeline

No history available yet.