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Fencer Vulns
medium 4.3

CVE-2026-84267 json

Gvfs: sftp: uninitialized heap disclosure in read_string()

published 2026-09-01 2 mo ago modified 2026-11-06 3 d ago also EUVD-2026-69296

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

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).

Patch / fix

  • GNOME gvfs 1.60.2
  • gvfs Debian 14 1.62.0-1

debian advisories DEBIAN-CVE-2026-84267

  • gvfs Ubuntu 22.04 LTS 1.48.2-0ubuntu1.3
  • gvfs Ubuntu 24.04 LTS 1.54.4-0ubuntu1~24.04.5
  • gvfs Ubuntu 26.04 LTS 1.60.0-1ubuntu0.2

ubuntu advisories UBUNTU-CVE-2026-84267

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • gvfs SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Desktop Applications 15 SP7 1.52.2-150600.3.9.1
  • gvfs SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 1.48.2-150400.4.15.1
  • gvfs SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 1.28.3-18.12.1

suse advisories SUSE-SU-2026:4240-1SUSE-SU-2026:4238-1SUSE-SU-2026:4200-1

  • gvfs openSUSE Leap 16.0 1.59.90-160000.3.1
  • gvfs openSUSE Tumbleweed 1.60.3-1.1

opensuse advisories openSUSE-SU-2026:21875-1openSUSE-SU-2026:11788-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-84267 updated cvss 4.3

gvfs: SFTP: uninitialized heap disclosure in read_string()

  • Red Hat Enterprise Linux 6 gvfs-afc, gvfs-smb, gvfs-fuse, gvfs-archive, gvfs-gphoto2, gvfs-obexftp, +1 more
    affected: workaround, no fix planned “To mitigate this vulnerability, do not connect to untrusted SFTP servers.”
  • Red Hat Enterprise Linux 7 gvfs, gvfs-afc, gvfs-afp, gvfs-goa, gvfs-mtp, gvfs-smb, +6 more Red Hat Enterprise Linux 8 gvfs, gvfs-afc, gvfs-afp, gvfs-goa, gvfs-mtp, gvfs-smb, +5 more Red Hat Enterprise Linux 9 gvfs, gvfs-goa, gvfs-mtp, gvfs-smb, gvfs-fuse, gvfs-client, +2 more Red Hat Enterprise Linux 10 gvfs 1.54.4-5.el10
    affected: workaround, no fix available “To mitigate this vulnerability, do not connect to untrusted SFTP servers.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.gnome.org https://gitlab.gnome.org/GNOME/gvfs/-/issues/861 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected products

  • GNOME gvfs
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.