CVE-2026-8927

critical

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`.

References

https://hackerone.com/reports/3744543

https://curl.se/docs/CVE-2026-8927.json

https://curl.se/docs/CVE-2026-8927.html

Details

Source: Mitre, NVD

Published: 2026-07-03

Updated: 2026-07-07

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

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

Severity: Critical

EPSS

EPSS: 0.0025