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Mallory
High

Denial of Service in GitLab CE/EE JSON validation middleware

IdentifiersCVE-2026-0958CWE-400

CVE-2026-0958 is a denial-of-service vulnerability in GitLab Community Edition (CE) and Enterprise Edition (EE) caused by the ability to bypass JSON validation middleware limits. GitLab states that this issue affects all versions from 18.4 before 18.6.6, 18.7 before 18.7.4, and 18.8 before 18.8.4. By circumventing the intended request validation limits in the JSON processing path, an unauthenticated attacker can submit requests that drive excessive memory consumption or CPU utilization, resulting in resource exhaustion and service degradation or outage.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to cause denial of service against a vulnerable GitLab instance. The primary impact is availability loss through CPU and/or memory exhaustion, which can slow the service significantly, make it unresponsive, or crash affected components depending on deployment characteristics and load.

Mitigation

If you can’t patch tonight, do this now.

No vendor workaround is specified in the provided content. If immediate patching is not possible, reduce exposure by limiting unauthenticated access to GitLab endpoints where feasible, applying network-layer filtering or WAF controls, enforcing request rate limiting, and monitoring for anomalous request patterns consistent with repeated JSON validation bypass attempts or sudden CPU/memory spikes.

Remediation

Patch, then assume compromise.

Upgrade GitLab CE/EE to a fixed release. GitLab indicates the issue is remediated in 18.6.6, 18.7.4, and 18.8.4. Self-managed installations should upgrade immediately to the appropriate patched version for their release track. GitLab.com is already patched according to the provided content.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
GitLabGitlabapplication

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What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

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Social activity4

Community discussion across Reddit, Mastodon, and other social sources.