CVE-2026-87866

CRITICAL
INFO Priority: 0.02 BB Relevance: 78/100
Published: 2026-10-20 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: High
I: High
A: None

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
curl curl 8.22.0

Bug Bounty Relevance

78 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

9.1 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploitation Probability

0.21%
Raw Score 0.002080
Percentile 10.9%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00208
2026-10-28
0.00208

Intelligence Sources

mitre ref →
nvd ref →