RHSA-2026:5475

Vulnerability from csaf_redhat - Published: 2026-03-23 17:29 - Updated: 2026-04-21 19:42
Summary
Red Hat Security Advisory: Red Hat Hardened Images RPM Release
Severity
Important
Notes
Topic: Red Hat Hardened Images RPM Release
Details: Red Hat Hardened Images RPM Release
Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.
CVE-2025-61984

A flaw was found in OpenSSH where control characters in usernames were not properly validated when sourced from untrusted inputs like the command line or configuration expansion. If a ProxyCommand is used, these control characters could modify command behavior, potentially leading to code execution.

5.3 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CWE-159 - Improper Handling of Invalid Use of Special Elements
Vendor Fix Red Hat Hardened Images RPM Release https://access.redhat.com/errata/RHSA-2026:5475
CVE-2025-61985

A flaw was found in OpenSSH where the SSH client accepted \0 (null) characters in ssh:// URIs. When a ProxyCommand is configured, these characters could alter how the command is parsed, potentially leading to code execution depending on how the proxy is set up.

5.3 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CWE-158 - Improper Neutralization of Null Byte or NUL Character
Vendor Fix Red Hat Hardened Images RPM Release https://access.redhat.com/errata/RHSA-2026:5475
CVE-2026-3497

A flaw was found in the OpenSSH GSSAPI (Generic Security Service Application Program Interface) delta patches, as included in various Linux distributions. A remote attacker could exploit this by sending an unexpected GSSAPI message type during the key exchange process. This occurs because the `sshpkt_disconnect()` function, when called on an error, does not properly terminate the process, leading to the continued execution of the program with uninitialized connection variables. Accessing these uninitialized variables can lead to undefined behavior, potentially resulting in information disclosure or a denial of service.

8.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
CWE-824 - Access of Uninitialized Pointer
Vendor Fix Red Hat Hardened Images RPM Release https://access.redhat.com/errata/RHSA-2026:5475
Workaround To mitigate this issue, disable GSSAPI key exchange in the OpenSSH server configuration. This prevents the server from processing GSSAPI messages, eliminating the vulnerability's attack surface. Edit `/etc/ssh/sshd_config` and add or modify the line: ``` GSSAPIKeyExchange no ``` After saving the changes, restart the `sshd` service for the mitigation to take effect. This action will prevent users from authenticating via GSSAPI. ``` # systemctl restart sshd ```
References
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          "details": "To mitigate this issue, disable GSSAPI key exchange in the OpenSSH server configuration. This prevents the server from processing GSSAPI messages, eliminating the vulnerability\u0027s attack surface.\n\nEdit `/etc/ssh/sshd_config` and add or modify the line:\n```\nGSSAPIKeyExchange no\n```\n\nAfter saving the changes, restart the `sshd` service for the mitigation to take effect. This action will prevent users from authenticating via GSSAPI.\n\n```\n# systemctl restart sshd\n```",
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        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "Red Hat Hardened Images:openssh-main@aarch64",
            "Red Hat Hardened Images:openssh-main@src",
            "Red Hat Hardened Images:openssh-main@x86_64"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Important"
        }
      ],
      "title": "openssh: OpenSSH GSSAPI: Information disclosure or denial of service due to uninitialized variables"
    }
  ]
}


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Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.



Detection rules are retrieved from Rulezet.