CVE-2026-8927
CRITICALCVSS 9.1/10EPSS 0.25%
Last modified
CVE-2026-8927 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.. EPSS estimates a 0.25% chance of exploitation in the next 30 days.
Description
When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| curl | curl | >= 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; >= 7.42.1, <= 7.42.1; >= 7.42.0, <= 7.42.0; >= 7.41.0, <= 7.41.0; >= 7.40.0, <= 7.40.0; >= 7.39.0, <= 7.39.0; >= 7.38.0, <= 7.38.0; >= 7.37.1, <= 7.37.1; >= 7.37.0, <= 7.37.0; >= 7.36.0, <= 7.36.0; >= 7.35.0, <= 7.35.0; >= 7.34.0, <= 7.34.0; >= 7.33.0, <= 7.33.0; >= 7.32.0, <= 7.32.0; >= 7.31.0, <= 7.31.0; >= 7.30.0, <= 7.30.0; >= 7.29.0, <= 7.29.0; >= 7.28.1, <= 7.28.1; >= 7.28.0, <= 7.28.0; >= 7.27.0, <= 7.27.0; >= 7.26.0, <= 7.26.0; >= 7.25.0, <= 7.25.0; >= 7.24.0, <= 7.24.0; >= 7.23.1, <= 7.23.1; >= 7.23.0, <= 7.23.0; >= 7.22.0, <= 7.22.0; >= 7.21.7, <= 7.21.7; >= 7.21.6, <= 7.21.6; >= 7.21.5, <= 7.21.5; >= 7.21.4, <= 7.21.4; >= 7.21.3, <= 7.21.3; >= 7.21.2, <= 7.21.2; >= 7.21.1, <= 7.21.1; >= 7.21.0, <= 7.21.0; >= 7.20.1, <= 7.20.1; >= 7.20.0, <= 7.20.0; >= 7.19.7, <= 7.19.7; >= 7.19.6, <= 7.19.6; >= 7.19.5, <= 7.19.5; >= 7.19.4, <= 7.19.4; >= 7.19.3, <= 7.19.3; >= 7.19.2, <= 7.19.2; >= 7.19.1, <= 7.19.1; >= 7.19.0, <= 7.19.0; >= 7.18.2, <= 7.18.2; >= 7.18.1, <= 7.18.1; >= 7.18.0, <= 7.18.0; >= 7.17.1, <= 7.17.1; >= 7.17.0, <= 7.17.0; >= 7.16.4, <= 7.16.4; >= 7.16.3, <= 7.16.3; >= 7.16.2, <= 7.16.2; >= 7.16.1, <= 7.16.1; >= 7.16.0, <= 7.16.0; >= 7.15.5, <= 7.15.5; >= 7.15.4, <= 7.15.4; >= 7.15.3, <= 7.15.3; >= 7.15.2, <= 7.15.2; >= 7.15.1, <= 7.15.1; >= 7.15.0, <= 7.15.0; >= 7.14.1, <= 7.14.1; >= 7.14.0, <= 7.14.0; >= 7.13.2, <= 7.13.2; >= 7.13.1, <= 7.13.1; >= 7.13.0, <= 7.13.0; >= 7.12.3, <= 7.12.3; >= 7.12.2, <= 7.12.2; >= 7.12.1, <= 7.12.1; >= 7.12.0, <= 7.12.0 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-8927?
When reusing a libcurl handle for sequential transfers driven by
environment-variable proxy configuration, libcurl fails to clear the proxy
authentication state between requests. Specifically, if the initial transfer
authenticates against `proxyA` using Digest auth, a subsequent transfer routed
through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended
solely for `proxyA`.
How severe is CVE-2026-8927?
CVE-2026-8927 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 0.25% probability of exploitation in the next 30 days.
How do I fix CVE-2026-8927?
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-2026-8927?
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