CVE-2026-1184: Insecure Deserialization in GitLab
Platform
gitlab
Component
gitlab
Fixed in
18.11.3
CVE-2026-1184 addresses an Insecure Deserialization vulnerability discovered in GitLab EE. This flaw allows an unauthenticated user to induce a denial of service (DoS) by uploading a specially crafted file. The vulnerability impacts GitLab EE versions ranging from 11.9.0 through 18.11.3, and is resolved in version 18.11.3.
Impact and Attack Scenarios
Successful exploitation of CVE-2026-1184 allows an attacker to disrupt GitLab services, rendering them unavailable to legitimate users. The attacker does not require authentication, significantly broadening the potential attack surface. The denial of service can manifest as system instability, performance degradation, or complete service outage. While the vulnerability doesn't directly lead to data exfiltration or code execution, the disruption of GitLab services can severely impact development workflows and project timelines. The impact is amplified in environments where GitLab is a critical component of the software development lifecycle.
Exploitation Context
CVE-2026-1184 was published on 2026-05-14. Its severity is currently assessed as Medium (CVSS 6.5). No public proof-of-concept (POC) code has been publicly released as of this writing. There are no indications of active exploitation campaigns targeting this vulnerability. The vulnerability is not currently listed on CISA Known Exploited Vulnerabilities (KEV) catalog.
Threat Intelligence
Exploit Status
CISA SSVC
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- Privileges Required
- Low — any valid user account is sufficient. Basic authenticated access required.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- None — no confidentiality impact. Attacker cannot read protected data.
- Integrity
- None — no integrity impact. Attacker cannot modify data.
- Availability
- High — complete crash or resource exhaustion. Full denial of service.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
Mitigation and Workarounds
The primary mitigation for CVE-2026-1184 is to upgrade GitLab EE to version 18.11.3 or later. If immediate upgrade is not feasible, consider implementing temporary workarounds such as restricting file uploads from unauthenticated users or implementing stricter file validation rules. Review GitLab's file upload policies and ensure they are enforced. Monitor GitLab logs for suspicious file upload activity. After upgrading, verify the fix by attempting a file upload with a known malicious payload (in a controlled environment) to confirm the vulnerability is no longer exploitable.
How to fix
Actualice GitLab a la versión 18.9.7 o superior, 18.10.6 o superior, o 18.11.3 o superior para mitigar la vulnerabilidad de deserialización de datos no confiables. Esta actualización aborda la validación incorrecta de archivos cargados, previniendo posibles ataques de denegación de servicio.
Frequently asked questions
What is CVE-2026-1184 — Insecure Deserialization in GitLab?
CVE-2026-1184 is a Medium severity vulnerability in GitLab EE allowing unauthenticated users to trigger a denial of service by uploading a crafted file due to improper validation. It affects versions 11.9.0–18.11.3.
Am I affected by CVE-2026-1184 in GitLab?
You are affected if you are running GitLab EE versions 11.9.0 through 18.11.3. Versions prior to 18.11.3 are vulnerable to denial of service attacks.
How do I fix CVE-2026-1184 in GitLab?
Upgrade GitLab EE to version 18.11.3 or later to resolve the vulnerability. Consider temporary workarounds like restricting unauthenticated file uploads if immediate upgrade is not possible.
Is CVE-2026-1184 being actively exploited?
As of the current assessment, there are no indications of active exploitation campaigns targeting CVE-2026-1184.
Where can I find the official GitLab advisory for CVE-2026-1184?
Refer to the official GitLab security advisory for CVE-2026-1184 on the GitLab website: [https://gitlab.com/security/advisories/](https://gitlab.com/security/advisories/)
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