CVE-2025-4877
Libssh: write beyond bounds in binary to base64 conversion functions
4.5CVSSMEDIUM
Description
There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a heap corruption. This issue affects only 32-bits builds of libssh.
CVSS Vector Breakdown
Exploitability
AV:LAttack VectorLocal
AC:HAttack ComplexityHigh
PR:LPrivileges RequiredLow
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:LConfidentialityLow
I:LIntegrityLow
A:LAvailabilityLow
Weaknesses
Affected Products
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
and 18 more affected products View all →
Attack Graph
Products CVE Techniques Tactics
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Exploitability
Official Patch Available
MITRE ATT&CK
2 techniques Initial Access
Privilege Escalation
References
https://access.redhat.com/errata/RHSA-2026:18683
access.redhat.com
https://access.redhat.com/security/cve/CVE-2025-4877
access.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2376193
bugzilla.redhat.com
and 10 more references View all →
Timeline
Published
Aug 20, 2025
Last Updated
May 19, 2026
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