CVE-2025-9086

Name	CVE-2025-9086
Description	1. A cookie is set using the `secure` keyword for `https://target` 2. curl is redirected to or otherwise made to speak with `http://target` (same hostname, but using clear text HTTP) using the same cookie set 3. The same cookie name is set - but with just a slash as path (`path='/'`). Since this site is not secure, the cookie should just be ignored. 4. A bug in the path comparison logic makes curl read outside a heap buffer boundary The bug either causes a crash or it potentially makes the comparison come to the wrong conclusion and lets the clear-text site override the contents of the secure cookie, contrary to expectations and depending on the memory contents immediately following the single-byte allocation that holds the path. The presumed and correct behavior would be to plainly ignore the second set of the cookie since it was already set as secure on a secure host so overriding it on an insecure host should not be okay.
Source	CVE (at NVD; CERT, 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 Package	Release	Version	Status
curl (PTS)	bullseye	7.74.0-1.3+deb11u13	vulnerable
	bullseye (security)	7.74.0-1.3+deb11u15	vulnerable
	bookworm	7.88.1-10+deb12u14	vulnerable
	bookworm (security)	7.88.1-10+deb12u5	vulnerable
	trixie	8.14.1-2	vulnerable
	forky	8.16.0-4	fixed
	sid	8.17.0~rc2-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
curl	source	(unstable)	8.16.0~rc2-1

Notes

[trixie] - curl <no-dsa> (Minor issue)
[bookworm] - curl <no-dsa> (Minor issue)
[bullseye] - curl <postponed> (Minor issue)
https://curl.se/docs/CVE-2025-9086.html
Introduced with: https://github.com/curl/curl/commit/f24dc09d209a2f91ca38d854f0c15ad93f3d7e2d (curl-7_31_0)
Fixed by: https://github.com/curl/curl/commit/c6ae07c6a541e0e96d0040afb62b45dd37711300 (rc-8_16_0-1)