CVE-2025-9086

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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTNIST
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
curlCNA
---
---
CISA-ADPADP
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 23%
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Debian Releases
Debian Product
Codename
curl
bullseye
postponed
trixie
no-dsa
bookworm
no-dsa
bullseye (security)
vulnerable
bookworm (security)
vulnerable
forky
8.17.0~rc2-1
fixed
sid
8.17.0~rc3-1
fixed