CVE-2023-36543Network attack vector

Authenticated request hang via task-filter regex

Published Jul 12, 2023 · Updated Oct 4, 2024

Regular expression denial of service in Apache Airflow before 2.6.3 allows remote authenticated users to hang a web request. DAG.partial_subset passes an attacker-supplied task filter to Python re.findall against every task ID, permitting catastrophic backtracking. A user with access to the affected DAG request path can tie up its worker thread, while the documented impact is limited to the current request.

CVSS severity6.5
Medium
EPSS probability1.57%
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 Apache Airflow before 2.6.3 allows remote authenticated users to hang a web request. DAG.partial_subset passes an attacker-supplied task filter to Python re.findall against every task ID, permitting catastrophic backtracking. A user with access to the affected DAG request path can tie up its worker thread, while the documented impact is limited to the current request.

The record

CVE
CVE-2023-36543
Published
Jul 12, 2023
Updated
Oct 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Airflow
Classifications
CWE-1333, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2024Record 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=0 <2.6.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Airflowversion=0 <2.6.3

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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