CVE-2026-55653
What it is
A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).
At a glance
- Exploitability
- Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.
- Exploit odds
- 0.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.5% in the next 30 days (EPSS).
- Severity: 4.3 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.5% · EPSS, next 30 days
- Weakness
- CWE-415
- Record status
- Modified
Affected
- Openbsd OpenSSH
- Redhat Hardened Images
- Redhat Openshift Container Platform 4.0
- Redhat Enterprise Linux 6.0
- Redhat Enterprise Linux 7.0
- Redhat Enterprise Linux 8.0
- Redhat Enterprise Linux 9.0
- Redhat Enterprise Linux 10.0
Attack profile CVSS 3.1 · 4.3
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-55653.md and follow it. Check whether this project is affected by CVE-2026-55653. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://access.redhat.com/security/cve/CVE-2026-55653
- https://bugzilla.redhat.com/show_bug.cgi?id=2462351
References
- https://access.redhat.com/errata/RHSA-2026:36759
- https://access.redhat.com/errata/RHSA-2026:47755
- https://access.redhat.com/errata/RHSA-2026:47756
- https://access.redhat.com/errata/RHSA-2026:47757
- https://access.redhat.com/errata/RHSA-2026:54387
- https://access.redhat.com/errata/RHSA-2026:58981
- https://access.redhat.com/errata/RHSA-2026:76748
- https://access.redhat.com/errata/RHSA-2026:76993
- https://access.redhat.com/errata/RHSA-2026:80513
- https://access.redhat.com/errata/RHSA-2026:82749
- https://access.redhat.com/errata/RHSA-2026:82750
- https://access.redhat.com/errata/RHSA-2026:82751
- https://access.redhat.com/errata/RHSA-2026:82752
- https://access.redhat.com/errata/RHSA-2026:82753
- https://access.redhat.com/errata/RHSA-2026:82754
- https://access.redhat.com/errata/RHSA-2026:82755
- https://access.redhat.com/errata/RHSA-2026:82756
- https://access.redhat.com/errata/RHSA-2026:82757
- https://access.redhat.com/errata/RHSA-2026:82758
- https://access.redhat.com/errata/RHSA-2026:82759
- https://access.redhat.com/errata/RHSA-2026:82761
- https://access.redhat.com/errata/RHSA-2026:82762
- https://access.redhat.com/errata/RHSA-2026:82763
- https://access.redhat.com/errata/RHSA-2026:82897
- https://access.redhat.com/errata/RHSA-2026:82898