CVE-2026-55653: Red Hat Enterprise Linux 10 · Double Free
Affects Red Hat Enterprise Linux 10Source CVE Database V5
Not known to be exploited · CVSS 4.3 Medium.
Data as of 5 Nov 2026, 11:40 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 4.3 |
|---|
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:LExploitation evidence
Disclosed: evidence found.
CVE published 23 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10openssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 10.0 Extended Update Supportopenssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8openssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9openssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutionsopenssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutionsopenssh | Affected– | Fixed in– |
AI-suggested
Red Hat has released updated OpenSSH packages (openssh-10.3p1-6.hum1) that fix this vulnerability. Users of Red Hat Enterprise Linux 10 should apply these official updates promptly to remediate the issue. Patch status is confirmed by Red Hat advisories. No additional mitigations are specified or required beyond applying the vendor-provided update.
Description
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).
References
- access.redhat.com/errata/RHSA-2026:36759 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47755 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47756 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:47757 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-55653 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2462351 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:54387 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:58981 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76748 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:76993 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:80513 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82749 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82750 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82751 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82752 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82753 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82754 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82755 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82756 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82757 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82758 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82759 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82761 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82762 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82763 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82897 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82898 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82899 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82900 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82901 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82902 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82903 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82904 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82907 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82908 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82909 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82910 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82912 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82913 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82914 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82915 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82916 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82917 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82918 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82920 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82921 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82922 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:82923 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:89739 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:91232 (opens in a new tab)