Vulnerability · Published Sep 1, 2026 · Assigned by redhat
CVE-2026-84267Gvfs: sftp: uninitialized heap disclosure in read_string()
Medium 4.3
In plain English
A medium-severity security flaw in gvfs from GNOME. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A 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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | gvfs | no fix listed | DEBIAN-CVE-2026-84267 |
| Debian:13 | gvfs | no fix listed | DEBIAN-CVE-2026-84267 |
| Debian:14 | gvfs | 1.62.0-1 | DEBIAN-CVE-2026-84267 |
| Ubuntu:22.04:LTS | gvfs | 1.48.2-0ubuntu1.3 | UBUNTU-CVE-2026-84267 |
| Ubuntu:24.04:LTS | gvfs | 1.54.4-0ubuntu1~24.04.5 | UBUNTU-CVE-2026-84267 |
| Ubuntu:26.04:LTS | gvfs | 1.60.0-1ubuntu0.2 | UBUNTU-CVE-2026-84267 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GNOME | gvfs | 1.10.0 – before 1.60.2 |
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 6 | see references |
| Red Hat | Red Hat Enterprise Linux 7 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
Weakness: CWE-908 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
References
- https://access.redhat.com/security/cve/CVE-2026-84267 vdb-entry, x_refsource_REDHAT
- RHBZ#2526466 issue-tracking, x_refsource_REDHAT
- https://gitlab.gnome.org/GNOME/gvfs/-/issues/861