CVE-2025-4877

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 v3 4.5 MEDIUM

4.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.0 / Impact : 3.4

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://access.redhat.com/errata/RHSA-2026:18683
https://access.redhat.com/security/cve/CVE-2025-4877
https://bugzilla.redhat.com/show_bug.cgi?id=2376193
https://git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d
https://www.libssh.org/security/advisories/CVE-2025-4877.txt

Configurations

No configuration.

History

19 May 2026, 14:16

Type	Values Removed	Values Added
References		() https://access.redhat.com/errata/RHSA-2026:18683 -

15 Apr 2026, 00:35

Type	Values Removed	Values Added
Summary		(es) Existe una vulnerabilidad en el paquete libssh: cuando un consumidor de libssh pasa un búfer de entrada inesperadamente grande a la función ssh_get_fingerprint_hash(), la función bin_to_base64() puede experimentar un desbordamiento de enteros que provoca una asignación insuficiente de memoria. En este caso, es posible que el programa realice una escritura fuera de los límites, lo que provoca una corrupción del montón. Este problema solo afecta a las compilaciones de 32 bits de libssh.

20 Aug 2025, 13:15

Type	Values Removed	Values Added
New CVE

Information

Published : 2025-08-20 13:15

Updated : 2026-06-30 11:16

NVD link : CVE-2025-4877

Mitre link : CVE-2025-4877

CVE.ORG link : CVE-2025-4877

JSON object : View

Products Affected

No product.

CWE

CWE-787

Out-of-bounds Write

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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.\nThis issue affects only 32-bits builds of libssh."}, {"lang": "es", "value": "Existe una vulnerabilidad en el paquete libssh: cuando un consumidor de libssh pasa un b\u00fafer de entrada inesperadamente grande a la funci\u00f3n ssh_get_fingerprint_hash(), la funci\u00f3n bin_to_base64() puede experimentar un desbordamiento de enteros que provoca una asignaci\u00f3n insuficiente de memoria. En este caso, es posible que el programa realice una escritura fuera de los l\u00edmites, lo que provoca una corrupci\u00f3n del mont\u00f3n. Este problema solo afecta a las compilaciones de 32 bits de libssh."}], "lastModified": "2026-06-30T11:16:23.063", "sourceIdentifier": "secalert@redhat.com"}