yaml is vulnerable to Stack Overflow via deeply nested YAML collections (eemeli yaml)

CVE-2026-33532
MEDIUM 4.3

At a glance

Source
NVD
EPSS
EPSS 0.49 % · percentile 42 ()
State
PUBLISHED
Published
Updated
Assigner
GitHub_M
NVD status
Analyzed

Description

`yaml` is a YAML parser and serialiser for JavaScript. Parsing a YAML document with a version of `yaml` on the 1.x branch prior to 1.10.3 or on the 2.x branch prior to 2.8.3 may throw a RangeError due to a stack overflow. The node resolution/composition phase uses recursive function calls without a depth bound. An attacker who can supply YAML for parsing can trigger a `RangeError: Maximum call stack size exceeded` with a small payload (~2–10 KB). The `RangeError` is not a `YAMLParseError`, so applications that only catch YAML-specific errors will encounter an unexpected exception type. Depending on the host application's exception handling, this can fail requests or terminate the Node.js process. Flow sequences allow deep nesting with minimal bytes (2 bytes per level: one `[` and one `]`). On the default Node.js stack, approximately 1,000–5,000 levels of nesting (2–10 KB input) exhaust the call stack. The exact threshold is environment-dependent (Node.js version, stack size, call stack depth at invocation). Note: the library's `Parser` (CST phase) uses a stack-based iterative approach and is not affected. Only the compose/resolve phase uses actual call-stack recursion. All three public parsing APIs are affected: `YAML.parse()`, `YAML.parseDocument()`, and `YAML.parseAllDocuments()`. Versions 1.10.3 and 2.8.3 contain a patch.

Weaknesses (CWE)

  • CWE-674 — Uncontrolled Recursion

References

Scores

VersionScoreVectorScored by
CVSS 3.1MEDIUM 4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:LGitHub_M
CVSS 3.1MEDIUM 4.3CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:LNVD · security-advisories@github.com (Secondary)

Advisories

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
eemeli · yamlaffected >= 2.0.0, < 2.8.3 ; affected >= 1.0.0, < 1.10.3

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD