CVE-2026-8927

NameCVE-2026-8927
DescriptionWhen 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`.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
curl (PTS)bullseye7.74.0-1.3+deb11u13vulnerable
bullseye (security)7.74.0-1.3+deb11u16vulnerable
bookworm7.88.1-10+deb12u15vulnerable
bookworm (security)7.88.1-10+deb12u5vulnerable
trixie8.14.1-2+deb13u4vulnerable
forky8.20.0-5vulnerable
sid8.21.0-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
curlsource(unstable)8.21.0~rc2-1

Notes

[trixie] - curl <no-dsa> (Minor issue)
[bookworm] - curl <postponed> (Minor issue; libcurl env-proxy Digest auth handle reuse)
[bullseye] - curl <postponed> (Minor issue; libcurl env-proxy Digest auth handle reuse)
https://curl.se/docs/CVE-2026-8927.html
Introduced with: https://github.com/curl/curl/commit/fc6eff13b5414caf6edf22d73a3239e074a04216 (curl-7_12_0)
Fixed by: https://github.com/curl/curl/commit/5c225384b8d52c67ce8259c6e4203bc57aacb567 (rc-8_21_0-1, curl-8_21_0)

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