CVE-2026-87866
UnknownEPSS 0.18%
Last modified
CVE-2026-87866 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 0.18% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| curl | curl | >= 8.22.0, <= 8.22.0; >= 8.21.0, <= 8.21.0; >= 8.20.0, <= 8.20.0; >= 8.19.0, <= 8.19.0; >= 8.18.0, <= 8.18.0; >= 8.17.0, <= 8.17.0; >= 8.16.0, <= 8.16.0; >= 8.15.0, <= 8.15.0; >= 8.14.1, <= 8.14.1; >= 8.14.0, <= 8.14.0; >= 8.13.0, <= 8.13.0; >= 8.12.1, <= 8.12.1; >= 8.12.0, <= 8.12.0; >= 8.11.1, <= 8.11.1; >= 8.11.0, <= 8.11.0; >= 8.10.1, <= 8.10.1; >= 8.10.0, <= 8.10.0; >= 8.9.1, <= 8.9.1; >= 8.9.0, <= 8.9.0; >= 8.8.0, <= 8.8.0; >= 8.7.1, <= 8.7.1; >= 8.7.0, <= 8.7.0; >= 8.6.0, <= 8.6.0; >= 8.5.0, <= 8.5.0; >= 8.4.0, <= 8.4.0; >= 8.3.0, <= 8.3.0; >= 8.2.1, <= 8.2.1; >= 8.2.0, <= 8.2.0; >= 8.1.2, <= 8.1.2; >= 8.1.1, <= 8.1.1; >= 8.1.0, <= 8.1.0; >= 8.0.1, <= 8.0.1; >= 8.0.0, <= 8.0.0; >= 7.88.1, <= 7.88.1; >= 7.88.0, <= 7.88.0; >= 7.87.0, <= 7.87.0; >= 7.86.0, <= 7.86.0; >= 7.85.0, <= 7.85.0; >= 7.84.0, <= 7.84.0; >= 7.83.1, <= 7.83.1; >= 7.83.0, <= 7.83.0; >= 7.82.0, <= 7.82.0; >= 7.81.0, <= 7.81.0; >= 7.80.0, <= 7.80.0; >= 7.79.1, <= 7.79.1; >= 7.79.0, <= 7.79.0; >= 7.78.0, <= 7.78.0; >= 7.77.0, <= 7.77.0; >= 7.76.1, <= 7.76.1; >= 7.76.0, <= 7.76.0; >= 7.75.0, <= 7.75.0; >= 7.74.0, <= 7.74.0; >= 7.73.0, <= 7.73.0; >= 7.72.0, <= 7.72.0; >= 7.71.1, <= 7.71.1; >= 7.71.0, <= 7.71.0; >= 7.70.0, <= 7.70.0; >= 7.69.1, <= 7.69.1; >= 7.69.0, <= 7.69.0; >= 7.68.0, <= 7.68.0; >= 7.67.0, <= 7.67.0; >= 7.66.0, <= 7.66.0; >= 7.65.3, <= 7.65.3; >= 7.65.2, <= 7.65.2; >= 7.65.1, <= 7.65.1; >= 7.65.0, <= 7.65.0; >= 7.64.1, <= 7.64.1; >= 7.64.0, <= 7.64.0; >= 7.63.0, <= 7.63.0; >= 7.62.0, <= 7.62.0; >= 7.61.1, <= 7.61.1; >= 7.61.0, <= 7.61.0; >= 7.60.0, <= 7.60.0; >= 7.59.0, <= 7.59.0; >= 7.58.0, <= 7.58.0; >= 7.57.0, <= 7.57.0; >= 7.56.1, <= 7.56.1; >= 7.56.0, <= 7.56.0; >= 7.55.1, <= 7.55.1; >= 7.55.0, <= 7.55.0; >= 7.54.1, <= 7.54.1; >= 7.54.0, <= 7.54.0; >= 7.53.1, <= 7.53.1; >= 7.53.0, <= 7.53.0; >= 7.52.1, <= 7.52.1; >= 7.52.0, <= 7.52.0; >= 7.51.0, <= 7.51.0; >= 7.50.3, <= 7.50.3; >= 7.50.2, <= 7.50.2; >= 7.50.1, <= 7.50.1; >= 7.50.0, <= 7.50.0; >= 7.49.1, <= 7.49.1; >= 7.49.0, <= 7.49.0; >= 7.48.0, <= 7.48.0; >= 7.47.1, <= 7.47.1; >= 7.47.0, <= 7.47.0; >= 7.46.0, <= 7.46.0; >= 7.45.0, <= 7.45.0; >= 7.44.0, <= 7.44.0; >= 7.43.0, <= 7.43.0 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-87866?
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.
How severe is CVE-2026-87866?
Severity scoring for CVE-2026-87866 is pending analysis. The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2026-87866?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-87866?
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