Memory Exhaustion Vulnerability in libssh During Key Exchange Processes
CVE-2025-8277

3.1LOW

Key Information:

Vendor

Red Hat
Status
Red Hat Enterprise Linux 10
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8
Vendor
CVE Published:
9 September 2025

What is CVE-2025-8277?

A vulnerability exists in libssh that compromises the key exchange (KEX) process. When a client sends multiple incorrect KEX guesses, the library fails to release memory during the rekey operations, leading to gradual memory exhaustion. This issue can cause client-side crashes, especially when utilized with libgcrypt, thus affecting the overall stability and availability of applications that rely on libssh.

References

https://access.redhat.com/security/cve/CVE-2025-8277
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2383888
issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:
3.1
Severity:
LOW
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Francesco Rollo for reporting this issue.
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CVE-2025-8277 : Memory Exhaustion Vulnerability in libssh During Key Exchange Processes