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CVE-2025-8277

Libssh: memory exhaustion via repeated key exchange in libssh

Published: Sep 9, 2025Updated: May 19, 2026 Sources: CVE List NVD BDUCWE-401
NVD MITRE
3.1CVSSLOW
EPSS Score
0.4%
Top 70.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually exhaust system memory. This issue can lead to crashes on the client side, particularly when using libgcrypt, which impacts application stability and availability.

CVSS Vector Breakdown

AV:NAC:HPR:LUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low
Open in CVSS calculator →

Weaknesses

CWE-401

Affected Products

Red Hat Enterprise LinuxRed Hat Inc.
On-premOS
Operating Systems / linux-distro
OpenShift Container PlatformRed Hat Inc.
SaaSSaaS Service
Cloud & SaaS / container-orchestration
Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
Astra Linux Special EditionООО «РусБИТех-Астра»
On-premOS
Operating Systems / linux-distro
АЛЬТ СП 10АО «ИВК»
On-premOS
Operating Systems / linux-distro
red hat inc.commercialUSOperating Systemsaka red hat
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
ооо «русбитех-астра»commercialRUOperating Systemsaka rusbitech-astra
ао «ивк»commercialRUOperating Systemsaka ivk
and 9 more affected products View all →

Exploitability

Official Patch Available
Workaround Available

References

https://access.redhat.com/security/cve/CVE-2025-8277
access.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2383888
bugzilla.redhat.com
https://access.redhat.com/security/cve/cve-2025-8277
access.redhat.com
and 9 more references View all →

Timeline

Published
Sep 9, 2025
Last Updated
May 19, 2026

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