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Fencer Vulns
medium 5.5

CVE-2023-24620 json

Esoteric YamlBeans XML Entity Expansion vulnerability

published 2023-08-25 3 y ago modified 2026-06-17 4 mo ago also GHSA-vj49-j7rc-h54f , EUVD-2023-2362

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

An issue was discovered in Esoteric YamlBeans through 1.15. A crafted YAML document is able perform am XML Entity Expansion attack against YamlBeans YamlReader. By exploiting the Anchor feature in YAML, it is possible to generate a small YAML document that, when read, is expanded to a large size, causing CPU and memory consumption, such as a Java Out-of-Memory exception.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/Contrast-Security-OSS/yamlbeans/blob/main/SECURITY.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
GitHub 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
maven com.esotericsoftware.yamlbeans:yamlbeans
<=1.15
 no fix listed

Classification

Weakness
  • CWE-611 Improper Restriction of XML External Entity Reference
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.