CVE-2026-1456
Published: 11 February 2026
Summary
CVE-2026-1456 is a medium-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Gitlab Gitlab. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application Exhaustion Flood (T1499.003); ranked at the 11.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Markdown preview input processing flaw directly enables application-layer resource exhaustion (CPU) DoS.
NVD Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.7 before 18.7.4, and 18.8 before 18.8.4 that could have allowed an unauthenticated user to cause denial of service through CPU exhaustion by submitting specially crafted markdown files…
more
that trigger exponential processing in markdown preview.
Deeper analysisAI
CVE-2026-1456 is a denial-of-service vulnerability in GitLab Community Edition (CE) and Enterprise Edition (EE), affecting all versions from 18.7 prior to 18.7.4 and from 18.8 prior to 18.8.4. The flaw enables CPU exhaustion through exponential processing triggered by specially crafted Markdown files submitted to the Markdown preview feature. It carries a CVSS v3.1 base score of 6.5 (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) and maps to CWE-770 (Allocation of Resources Without Limits or Throttling).
An unauthenticated user, as described in the advisory, can exploit the vulnerability by submitting malicious Markdown files, causing significant CPU resource consumption and disrupting service availability. While the CVSS vector indicates low privileges (PR:L) are required, the impact is confined to high availability disruption with no effects on confidentiality or integrity.
GitLab has remediated the issue via patch releases, including GitLab 18.8.4, as outlined in their release notes at https://about.gitlab.com/releases/2026/02/10/patch-release-gitlab-18-8-4-released/. Administrators should upgrade affected instances to GitLab 18.7.4 or later, or 18.8.4 or later. Further technical details are available in the GitLab issue tracker at https://gitlab.com/gitlab-org/gitlab/-/issues/587688 and the HackerOne disclosure report at https://hackerone.com/reports/3517928.
Details
- CWE(s)