CVE-2026-0966: Buffer Underwrite ('Buffer Underflow') in Red Hat Red Hat Hardened Images
CVE-2026-0966 is a medium severity buffer underwrite vulnerability in the Red Hat Hardened Images, specifically in the ssh_get_hexa() API function when it receives zero-length input. This function is used internally by ssh_get_fingerprint_hash() and ssh_print_hexa(), and also in the GSSAPI code for logging OIDs during GSSAPI authentication. The vulnerability can be triggered remotely if the server allows GSSAPI authentication and logging verbosity is set to SSH_LOG_PACKET or higher, potentially causing a denial of service of the per-connection daemon process.
AI Analysis
Technical Summary
The vulnerability exists in the ssh_get_hexa() function of Red Hat Hardened Images, where providing zero-length input leads to a buffer underwrite (buffer underflow). This function is used internally by other SSH functions and in the GSSAPI authentication logging code. When GSSAPI authentication is enabled and logging verbosity is at least SSH_LOG_PACKET (3), a remote attacker can trigger this condition, causing a denial of service by crashing the per-connection daemon process. The CVSS v3.0 score is 6.5 (medium severity) with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to integrity and availability.
Potential Impact
The vulnerability can cause a denial of service (DoS) by crashing the per-connection SSH daemon process when triggered remotely under specific conditions (GSSAPI authentication enabled and verbose logging). There is no confidentiality impact reported, and no known exploits in the wild. The integrity impact is low, and availability impact is low to medium due to potential self-DoS.
Mitigation Recommendations
Red Hat has published security advisories related to this vulnerability (https://access.redhat.com/errata/RHSA-2026:7067 and https://access.redhat.com/security/cve/CVE-2026-0966). However, the provided advisory content does not explicitly confirm the availability of a patch or update fixing this issue. Therefore, patch status is not yet confirmed — check the Red Hat advisories regularly for updates and apply any released updates promptly. In the meantime, if feasible, consider disabling GSSAPI authentication or reducing SSH logging verbosity below SSH_LOG_PACKET to mitigate the risk of triggering the vulnerability.
CVE-2026-0966: Buffer Underwrite ('Buffer Underflow') in Red Hat Red Hat Hardened Images
Description
CVE-2026-0966 is a medium severity buffer underwrite vulnerability in the Red Hat Hardened Images, specifically in the ssh_get_hexa() API function when it receives zero-length input. This function is used internally by ssh_get_fingerprint_hash() and ssh_print_hexa(), and also in the GSSAPI code for logging OIDs during GSSAPI authentication. The vulnerability can be triggered remotely if the server allows GSSAPI authentication and logging verbosity is set to SSH_LOG_PACKET or higher, potentially causing a denial of service of the per-connection daemon process.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in the ssh_get_hexa() function of Red Hat Hardened Images, where providing zero-length input leads to a buffer underwrite (buffer underflow). This function is used internally by other SSH functions and in the GSSAPI authentication logging code. When GSSAPI authentication is enabled and logging verbosity is at least SSH_LOG_PACKET (3), a remote attacker can trigger this condition, causing a denial of service by crashing the per-connection daemon process. The CVSS v3.0 score is 6.5 (medium severity) with network attack vector, low attack complexity, no privileges or user interaction required, and impact limited to integrity and availability.
Potential Impact
The vulnerability can cause a denial of service (DoS) by crashing the per-connection SSH daemon process when triggered remotely under specific conditions (GSSAPI authentication enabled and verbose logging). There is no confidentiality impact reported, and no known exploits in the wild. The integrity impact is low, and availability impact is low to medium due to potential self-DoS.
Mitigation Recommendations
Red Hat has published security advisories related to this vulnerability (https://access.redhat.com/errata/RHSA-2026:7067 and https://access.redhat.com/security/cve/CVE-2026-0966). However, the provided advisory content does not explicitly confirm the availability of a patch or update fixing this issue. Therefore, patch status is not yet confirmed — check the Red Hat advisories regularly for updates and apply any released updates promptly. In the meantime, if feasible, consider disabling GSSAPI authentication or reducing SSH logging verbosity below SSH_LOG_PACKET to mitigate the risk of triggering the vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-01-14T21:54:59.132Z
- Cvss Version
- 3.0
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/errata/RHSA-2026:7067","vendor":"Red Hat"},{"url":"https://access.redhat.com/security/cve/CVE-2026-0966","vendor":"Red Hat"}]
Threat ID: 69c5a54b3c064ed76fcfc842
Added to database: 3/26/2026, 9:29:47 PM
Last enriched: 5/11/2026, 2:00:28 AM
Last updated: 5/11/2026, 5:04:22 AM
Views: 77
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.