CVE-2023-3364Public exploitNetwork attack vector

Service interruption via AutolinkFilter regex backtracking

Published Aug 1, 2023 · Updated Nov 20, 2025

Regular expression denial of service in affected GitLab CE/EE releases allows remote attackers to interrupt service via crafted Markdown. AutolinkFilter applies a trailing-HTML-entity regular expression to escaped ampersands, causing severe backtracking on nonmatching input. An unauthenticated request to a public group's preview_markdown endpoint can consume a CPU core until timeout; sustained requests can make the instance unresponsive.

CVSS severity7.5
High
EPSS probability44.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Regular expression denial of service in affected GitLab CE/EE releases allows remote attackers to interrupt service via crafted Markdown. AutolinkFilter applies a trailing-HTML-entity regular expression to escaped ampersands, causing severe backtracking on nonmatching input. An unauthenticated request to a public group's preview_markdown endpoint can consume a CPU core until timeout; sustained requests can make the instance unresponsive.

The record

CVE
CVE-2023-3364
Published
Aug 1, 2023
Updated
Nov 20, 2025
Vendor
GitLab
Product
GitLab
Classifications
CWE-1333, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=16.1 <16.1.3
  2. Affected versionversion=16.2 <16.2.2
  3. Affected versionversion=8.14 <16.0.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GitLab · GitLabversion=16.1 <16.1.3; version=16.2 <16.2.2; version=8.14 <16.0.8

Published CVSS scores

7.5GitLab Inc.CVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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
T1499.003Application Exhaustion Flood

Public exploit references

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

Technologies

Your stack

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Your stack

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