CVE-2026-8927

critical · 9.1

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`.

9.1

CVSS

0.5%

EPSS (exploit prob.)

42nd

EPSS percentile

2026-07-03

Published

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

Weaknesses

CWE-294

Affected products

Vendor	Product	Affected versions
haxx	curl	>= 7.12.0, < 8.21.0

Check a specific version with /api/v1/cve/match.

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

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-8927