Denial of service via unbounded entity expansion
Published Dec 18, 2022 · Updated Apr 15, 2025
Denial of service in xml-conduit before 1.9.1.0 allows remote attackers to hang XML-processing applications via crafted DOCTYPE entities. The DOCTYPE expansion path in Text.XML.Stream.Parse fails to detect recursive cycles or bound expanded text, so hostile definitions recurse indefinitely or grow explosively. Reachability requires a consuming application to parse attacker-controlled XML; the bounded consequence is a hang or resource-exhaustion service interruption.
Summary
What happened
Denial of service in xml-conduit before 1.9.1.0 allows remote attackers to hang XML-processing applications via crafted DOCTYPE entities. The DOCTYPE expansion path in Text.XML.Stream.Parse fails to detect recursive cycles or bound expanded text, so hostile definitions recurse indefinitely or grow explosively. Reachability requires a consuming application to parse attacker-controlled XML; the bounded consequence is a hang or resource-exhaustion service interruption.
The record
- CVE
- CVE-2021-4249
- Published
- Dec 18, 2022
- Updated
- Apr 15, 2025
- Vendor
- Michael Snoyman
- Product
- xml-conduit
- Classifications
- CWE-404, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 18, 2022CVE publishedPublication date reported by the CVE source.
- Apr 15, 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.
- Affected versionversion=0.5.0
- Affected versionversion=0.5.0.1
- Affected versionversion=0.5.1
- Affected versionversion=0.5.1.1
- Affected versionversion=0.5.1.2
- Affected versionversion=0.5.2
- Affected versionversion=0.5.3
- Affected versionversion=0.5.3.1
- Affected versionversion=0.5.4
- Affected versionversion=0.6.0
- Affected versionversion=0.6.1
- Affected versionversion=0.7.0
- Affected versionversion=0.7.0.1
- Affected versionversion=0.7.0.2
- Affected versionversion=0.7.0.3
- Affected versionversion=1.0.0
- Affected versionversion=1.0.1
- Affected versionversion=1.0.1.1
- Affected versionversion=1.0.2
- Affected versionversion=1.0.2.1
- Affected versionversion=1.0.3
- Affected versionversion=1.0.3.1
- Affected versionversion=1.0.3.2
- Affected versionversion=1.0.3.3
- Affected versionversion=1.1.0
- Affected versionversion=1.1.0.1
- Affected versionversion=1.1.0.2
- Affected versionversion=1.1.0.3
- Affected versionversion=1.1.0.4
- Affected versionversion=1.1.0.5
- Affected versionversion=1.1.0.6
- Affected versionversion=1.1.0.7
- Affected versionversion=1.1.0.8
- Affected versionversion=1.1.0.9
- Affected versionversion=1.2.0
- Affected versionversion=1.2.0.1
- Affected versionversion=1.2.0.2
- Affected versionversion=1.2.0.3
- Affected versionversion=1.2.1
- Affected versionversion=1.2.1.1
- Affected versionversion=1.2.2
- Affected versionversion=1.2.3
- Affected versionversion=1.2.3.1
- Affected versionversion=1.2.3.2
- Affected versionversion=1.2.3.3
- Affected versionversion=1.2.4
- Affected versionversion=1.2.5
- Affected versionversion=1.2.5.1
- Affected versionversion=1.2.6
- Affected versionversion=1.3.0
- Affected versionversion=1.3.1
- Affected versionversion=1.3.2
- Affected versionversion=1.3.3
- Affected versionversion=1.3.3.1
- Affected versionversion=1.3.4
- Affected versionversion=1.3.4.1
- Affected versionversion=1.3.4.2
- Affected versionversion=1.3.5
- Affected versionversion=1.4.0
- Affected versionversion=1.4.0.1
- Affected versionversion=1.4.0.2
- Affected versionversion=1.4.0.3
- Affected versionversion=1.4.0.4
- Affected versionversion=1.5.0
- Affected versionversion=1.5.1
- Affected versionversion=1.6.0
- Affected versionversion=1.7.0
- Affected versionversion=1.7.0.1
- Affected versionversion=1.7.1.0
- Affected versionversion=1.7.1.1
- Affected versionversion=1.7.1.2
- Affected versionversion=1.8.0
- Affected versionversion=1.8.0.1
- Affected versionversion=1.9.0.0
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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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