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kaml has potential denial of service while parsing input with anchors and aliases

High severity GitHub Reviewed Published Mar 18, 2023 in charleskorn/kaml • Updated Mar 20, 2023

Package

maven com.charleskorn.kaml:kaml (Maven)

Affected versions

< 0.53.0

Patched versions

0.53.0

Description

Impact

Applications that use kaml to parse untrusted input containing anchors and aliases may consume excessive memory and crash.

Patches

Version 0.53.0 and later default to refusing to parse YAML documents containing anchors and aliases.

Workarounds

None.

References

Wikipedia has an explanation of this class of vulnerability: billion laughs attack

Acknowledgements

Thank you to @gdude2002 for reporting this issue.

References

@charleskorn charleskorn published to charleskorn/kaml Mar 18, 2023
Published by the National Vulnerability Database Mar 20, 2023
Published to the GitHub Advisory Database Mar 20, 2023
Reviewed Mar 20, 2023
Last updated Mar 20, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.159%
(53rd percentile)

Weaknesses

CVE ID

CVE-2023-28118

GHSA ID

GHSA-c24f-2j3g-rg48

Source code

Credits

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