CVE-2026-84267

NameCVE-2026-84267
DescriptionA flaw was found in the SFTP backend in gvfs. When mounting a share, a malicious SFTP server can cause read_string() to allocate a buffer with a certain length but the function does not verify that the buffer is completely filled, leaving the remainder of the buffer containing uninitialized heap contents. If the server sends a short FXP_HANDLE reply, these uninitialized bytes are taken as the file handle. The client will then echo these uninitialized bytes back to the server on all subsequent requests using that handle. With a length of 128 bytes, this issue allows the malicious server to deterministically read uninitialized heap memory from the gvfsd-sftp process, leaking its heap base and the load address of the libgio library, resulting in a deterministic defeat of Address Space Layout Randomization (ASLR).
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
gvfs (PTS)bookworm1.50.3-1+deb12u1vulnerable
trixie1.57.2-2+deb13u1vulnerable
forky, sid1.60.0-2vulnerable

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
gvfssource(unstable)(unfixed)

Notes

https://gitlab.gnome.org/GNOME/gvfs/-/issues/861
https://gitlab.gnome.org/GNOME/gvfs/-/merge_requests/340
Fixed by: https://gitlab.gnome.org/GNOME/gvfs/-/commit/d9a59b8e385189b4783d9b66ca475f530fb26693 (1.61.90)
Fixed by: https://gitlab.gnome.org/GNOME/gvfs/-/commit/015bf91450370a0717b91742feeb8f22e8b0243e (1.60.2)

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