CVE-2023-24620 — An issue was discovered in Esoteric YamlBeans through 1

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

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-08-25T00:00:00.000Z
• Last modified: 2024-10-02T18:08:16.309Z

09References

• github.com — https://github.com/EsotericSoftware
• contrastsecurity.com — https://contrastsecurity.com
• github.com — https://github.com/Contrast-Security-OSS/yamlbeans/blob/main/SECURITY.md