Low severity · published Sep 9, 2025
CVE-2025-8277
Libssh: memory exhaustion via repeated key exchange in libssh
3.1
CVSS
0.4%
EPSS
No
On KEV
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
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 9 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat OpenShift Container Platform 4 · Red Hat
All versions, or not specified · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-8277
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-8277
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:18683
access.redhat.com
https://access.redhat.com/security/cve/CVE-2025-8277
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2383888
www.libssh.org
https://www.libssh.org/security/advisories/CVE-2025-8277.txt
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