CVE-2026-8927

9.1 criticalEPSS 0.5%

Critical (9.1) in haxx curl. EPSS 0.5% chance of exploitation in the next 30 days.

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`.

Severity

CVSS 3.1

9.1 critical

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

EPSS: 0.5% chance of exploitation in the next 30 days; higher than 42% of CVEs (scores of 2026-10-31)
CWE: CWE-294
Published: 2026-07-03
Modified: 2026-09-15
Record from: the NVD, synced 2026-10-19

Affected

haxx:curl

References

https://curl.se/docs/CVE-2026-8927.html
https://curl.se/docs/CVE-2026-8927.json
https://hackerone.com/reports/3744543
https://hackerone.com/reports/3744543

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