CVE-2026-55653 (GCVE-0-2026-55653)
Vulnerability from cvelistv5 – Published: 2026-06-23 03:36 – Updated: 2026-09-01 12:38
VLAI
EPSS
VEX
Title
Openssh: double free in red hat enterprise linux versions of openssh dh-gex client path during fips known-group validation leads to client-side denial of service
Summary
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).
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-23 14:30 UTC
CWE
- CWE-415 - Double Free
Assigner
References
8 references
| URL | Tags |
|---|---|
| https://access.redhat.com/errata/RHSA-2026:36759 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:47755 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:47756 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:47757 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:54387 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/errata/RHSA-2026:58981 | vendor-advisoryx_refsource_REDHAT |
| https://access.redhat.com/security/cve/CVE-2026-55653 | vdb-entryx_refsource_REDHAT |
| https://bugzilla.redhat.com/show_bug.cgi?id=2462351 | issue-trackingx_refsource_REDHAT |
Impacted products
11 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 |
Unaffected:
0:9.9p1-25.el10_2 , < *
(rpm)
cpe:/o:redhat:enterprise_linux:10.2 |
||
| Red Hat | Red Hat Enterprise Linux 8 |
Unaffected:
0:8.0p1-30.el8_10 , < *
(rpm)
cpe:/a:redhat:enterprise_linux:8::appstream cpe:/o:redhat:enterprise_linux:8::baseos |
||
| Red Hat | Red Hat Enterprise Linux 9 |
Unaffected:
0:9.9p1-9.el9_8 , < *
(rpm)
cpe:/a:redhat:enterprise_linux:9::appstream cpe:/o:redhat:enterprise_linux:9::baseos |
||
| Red Hat | Red Hat Hardened Images |
Unaffected:
10.3p1-6.hum1 , < *
(rpm)
cpe:/a:redhat:hummingbird:1 |
||
| Red Hat | Red Hat Update Infrastructure 5 |
Unaffected:
1786435483 , < *
(rpm)
cpe:/a:redhat:rhui:5::el9 |
||
| Red Hat | Red Hat Update Infrastructure 5 |
Unaffected:
1786533529 , < *
(rpm)
cpe:/a:redhat:rhui:5::el9 |
||
| Red Hat | Red Hat Update Infrastructure 5 |
Unaffected:
1787135742 , < *
(rpm)
cpe:/a:redhat:rhui:5::el9 |
||
| Red Hat | Red Hat Update Infrastructure 5 |
Unaffected:
1787241260 , < *
(rpm)
cpe:/a:redhat:rhui:5::el9 |
||
| Red Hat | Red Hat Enterprise Linux 6 |
cpe:/o:redhat:enterprise_linux:6
|
||
| Red Hat | Red Hat Enterprise Linux 7 |
cpe:/o:redhat:enterprise_linux:7
|
||
| Red Hat | Red Hat OpenShift Container Platform 4 |
cpe:/a:redhat:openshift:4
|
Date Public
2026-06-22 23:17
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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