Medium [CVE-2025-5351] Libssh: double free vulnerability in libssh key export functions
This medium-severity Red Hat Linux advisory covers CVE-2025-5351 affecting Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6.
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Summary
A flaw was found in the key export functionality of libssh. The issue occurs in the internal function responsible for converting cryptographic keys into serialized formats.
During error handling, a memory structure is freed but not cleared, leading to a potential double free issue if an additional failure occurs later in the function. This condition may result in heap corruption or application instability in low-memory scenarios, posing a risk to system reliability where key export operations are performed.
The Red Hat Product Security team has rated the severity of this issue as Moderate. The vulnerability arises from a double free condition that is only exploitable under rare and constrained scenarios such as low memory environments.
Despite the restricted preconditions, the flaw still presents a stability concern for services utilizing libssh in sensitive environments. Weakness: CWE-415.
Affected Red Hat products: Red Hat Enterprise Linux 9; Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat OpenShift Container Platform 4. Will not fix / out of support: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7.
Red Hat fixing advisory: RHSA-2026:18683.
Affected products named by the advisory: Red Hat package: libssh2.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
- libssh-0:0.10.4-18.el9
- RHSA-2026:18683
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Administrators should apply vendor-supplied patches as soon as they become available.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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