CVE-2026-33532
mediumpriority · track · 10EPSS 0.005 · 42 %ileexploit · PoCDEEURUUSEPSS · scored 2026-10-27
`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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
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weaknesses
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exploits (1)
Public proof-of-concept and weaponised exploit code.
- danwulff/astro_CVE-2026-33532danwulff/astro_CVE-2026-33532PoC · poc_in_github
affected products (12)
Products and version ranges known to be affected.
advisories (4)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1407IBM App Connect Enterprise Certified Container: Mehrere SchwachstellenDeutsch2026-05-06csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise Certified Container ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Cross-Site-Scripting-Angriffe durchzuführen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.
- WID-SEC-W-2026-2933Splunk SOAR: Mehrere SchwachstellenDeutsch2026-08-19csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Splunk SOAR ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen SQL-Injection Angriff durchzuführen, um einen Cross-Site Scripting Angriff durchzuführen, und um beliebigen Programmcode auszuführen.
- WID-SEC-W-2026-3046IBM Concert: Mehrere SchwachstellenDeutsch2026-08-26csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM Concert ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, um einen SQL-Injection Angriff durchzuführen und um Sicherheitsvorkehrungen zu umgehen.
- GHSA-48c2-rrv3-qjmpyaml is vulnerable to Stack Overflow via deeply nested YAML collections2026-03-25ghsa · osvUS
Parsing a YAML document with `yaml` 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()`. ### PoC ```javascript const YAML = require('yaml'); // ~10 KB payload: 5000 levels of nested flow sequences const payload = '['.repeat(5000) + '1' + ']'.repeat(5000); try { YAML.parse(payload); } catch (e) { console.log(e.constructor.name); // RangeError (NOT YAMLParseError) console.log(e.message); // Maximum call stack size exceeded } ``` Test environment: Node.js v24.12.0, macOS darwin arm64 | Version | Nesting Depth | Input Size | Result | |---|---|---|---| | 1.0.0 | 5,000 | 10,001 B | RangeError | | 1.10.2 | 5,000 | 10,001 B | RangeError | | 2.0.0 | 5,000 | 10,001 B | RangeError | | 2.8.2 | 5,000 | 10,001 B | RangeError | | 2.8.3 | 5,000 | 10,001 B | YAMLParseError | Depth threshold on yaml 2.8.2: | Nesting Depth | Input Size | Result | |---|---|---| | 500 | 1,001 B | Parses successfully | | 1,000 | 2,001 B | RangeError (threshold varies by stack size) | | 5,000 | 10,001 B | RangeError |
also known as (4)
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sources
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references (13)
External citations — patches, advisories, analysis.
- https://github.com/eemeli/yaml/commit/1e84ebbea7ec35011a4c61bbb820a529ee4f359bcnnvd
- https://github.com/eemeli/yaml/releasesPatchcnnvd
- https://github.com/eemeli/yaml/releases/tag/v1.10.3cnnvd
- https://github.com/eemeli/yaml/releases/tag/v2.8.3cnnvd
- https://github.com/eemeli/yaml/security/advisories/GHSA-48c2-rrv3-qjmpcnnvd
- https://github.com/eemeli/yaml/commit/1e84ebbea7ec35011a4c61bbb820a529ee4f359benisa_euvd
- https://github.com/eemeli/yaml/releases/tag/v1.10.3enisa_euvd
- https://github.com/eemeli/yaml/releases/tag/v2.8.3enisa_euvd
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