CVE-2023-2199Public exploitNetwork attack vector

Unauthenticated denial of service via regex backtracking

Published Jun 7, 2023 · Updated Jan 7, 2025

Regular expression denial of service in affected GitLab CE/EE releases allows remote attackers to interrupt service through Markdown preview. FrontMatterFilter passes attacker-controlled Markdown to Gitlab::FrontMatter::PATTERN, whose optional and non-greedy groups trigger severe backtracking on a crafted nonmatch. An unauthenticated request to a public group preview can occupy one CPU core until timeout; repeated requests can make the instance unavailable.

CVSS severity7.5
High
EPSS probability1.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Regular expression denial of service in affected GitLab CE/EE releases allows remote attackers to interrupt service through Markdown preview. FrontMatterFilter passes attacker-controlled Markdown to Gitlab::FrontMatter::PATTERN, whose optional and non-greedy groups trigger severe backtracking on a crafted nonmatch. An unauthenticated request to a public group preview can occupy one CPU core until timeout; repeated requests can make the instance unavailable.

The record

CVE
CVE-2023-2199
Published
Jun 7, 2023
Updated
Jan 7, 2025
Vendor
GitLab
Product
GitLab
Classifications
CWE-1333, CAPEC-492, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 7, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 7, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>=12.0, <15.10.8
  2. Affected versionversion=>=15.11, <15.11.7
  3. Affected versionversion=>=16.0, <16.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GitLab · GitLabversion=>=12.0, <15.10.8; version=>=15.11, <15.11.7; version=>=16.0, <16.0.2

Published CVSS scores

7.5GitLabCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
CAPEC-492Regular Expression Exponential Blowup
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo