CVE-2026-40254

Name	CVE-2026-40254
Description	FreeRDP is a free implementation of the Remote Desktop Protocol. Versions prior to 3.25.0 have an off-by-one in the path traversal filter in `channels/drive/client/drive_file.c`. The `contains_dotdot()` function catches `../` and `..\` mid-path but misses `..` when it's the last component with no trailing separator. A rogue RDP server can read, list, or write files one directory above the client's shared folder through RDPDR requests. This requires the victim to connect with drive redirection enabled. Version 3.25.0 patches the issue.
Source	CVE (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 Package	Release	Version	Status
freerdp2 (PTS)	bullseye	2.3.0+dfsg1-2+deb11u1	vulnerable
	bullseye (security)	2.3.0+dfsg1-2+deb11u3	vulnerable
	bookworm	2.11.7+dfsg1-6~deb12u1	vulnerable
freerdp3 (PTS)	trixie	3.15.0+dfsg-2.1	vulnerable
	forky	3.24.2+dfsg-1	vulnerable
	sid	3.26.0+dfsg-1	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
freerdp2	source	(unstable)	(unfixed)
freerdp3	source	(unstable)	3.25.0+dfsg-1

Notes

[trixie] - freerdp3 <no-dsa> (Minor issue)
[bookworm] - freerdp2 <no-dsa> (Minor issue)
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3xpj-m4hx-8vmx