Bug 2369367 (CVE-2025-5351)

Summary: CVE-2025-5351 libssh: Double Free Vulnerability in libssh Key Export Functions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: adudiak, kshier, omaciel, security-response-team, stcannon, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Deadline: 2025-06-24   

Description OSIDB Bzimport 2025-05-30 07:17:41 UTC 
A Double Free vulnerability exists in libssh’s key export mechanism when built against OpenSSL 3.0 or later. The flaw lies in the pki_key_to_blob() function, where a memory structure (params) is deallocated during error handling but not properly nullified. If a subsequent operation encounters an error, the same structure may be freed again, leading to undefined behavior and potential process crashes. Although exploitation requires authenticated access and specific memory failure conditions, the flaw could be leveraged to destabilize applications using libssh for exporting SSH key material.

Affected versions : libssh >= 0.10.0, built with OpenSSL >= 3.0