Esoteric YamlBeans Unsafe Deserialization vulnerability

published 2023-08-25 3 y ago modified 2026-06-17 4 mo ago also GHSA-jm7r-4pg6-gf26 , EUVD-2023-2320

cvss: 7.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

An issue was discovered in Esoteric YamlBeans through 1.15. It allows untrusted deserialisation to Java classes by default, where the data and class are controlled by the author of the YAML document being processed.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 2 y ago (2024-10-02)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% 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	7.8	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

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

Classification

Weakness

CWE-502 Deserialization of Untrusted Data

References

github.com /Contrast-Security-OSS/yamlbeans/blob/main/SECURITY.md
web, exploit, third-party-advisory
github.com /EsotericSoftware
web, third-party-advisory
contrastsecurity.com
web, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2023-24621
advisory
github.com /EsotericSoftware/yamlbeans
package

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.

Summary