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CVE-2025-5987

Libssh: invalid return code for chacha20 poly1305 with openssl backend

Published: Jul 7, 2025Updated: Mar 5, 2026 Sources: CVE List NVD BDUCWE-393
NVD MITRE
8.1CVSSHIGH
EPSS Score
1.4%
Top 30.3%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-393

Affected Products

libsshlibssh
Library
OSS Libraries / generic-library
Red Hat Enterprise Linux 10Red Hat
On-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 10.0 Extended Update SupportRed Hat
On-premOS
Operating Systems / linux-distro
Red Hat Enterprise Linux 9Red Hat
On-premOS
Operating Systems / linux-distro
libsshoss-projectOSS Librariesaka libssh2 (related, sometimes confused)
red hatcommercialUSOperating Systemsaka red hat
and 27 more affected products View all →

Exploitability

Official Patch Available

References

https://access.redhat.com/errata/RHSA-2025:23483
access.redhat.com
https://access.redhat.com/errata/RHSA-2025:23484
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:0427
access.redhat.com
and 26 more references View all →

Timeline

Published
Jul 7, 2025
Last Updated
Mar 5, 2026

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