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).
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

To mitigate this vulnerability, do not connect to untrusted SFTP servers.

History

Tue, 01 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
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).
Title Gvfs: sftp: uninitialized heap disclosure in read_string()
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-908
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-09-01T17:34:35.705Z

Reserved: 2026-09-01T14:05:54.144Z

Link: CVE-2026-84267

cve-icon Vulnrichment

Updated: 2026-09-01T15:50:35.707Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-01T16:17:37.007

Modified: 2026-09-01T21:03:04.987

Link: CVE-2026-84267

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses