CVE-2026-57077
YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len.
In the bundled libsyck newline_len and is_newline dereference the scan pointer, and the following byte for a "\r\n" pair, with no NUL-terminator or bounds check. During block-scalar lexing at a document boundary the scan runs one byte past the heap lexer buffer. This is an incomplete fix of CVE-2025-11683, on a lexer path the earlier fix did not cover.
Any caller that runs Load or LoadFile on an untrusted document with a block scalar at a document boundary reaches the over-read.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- Puntuación base: 7.7
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.19%
- Percentil entre todas las CVEs puntuadas: 8
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1059Command and Scripting Interpreterexecution75 %
AV:L sin UI permite escalada local; out-of-bounds read en parser YAML puede derivar en RCE mediante corrupción de memoria o ejecución de código en procesos que cargan documentos YAML.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-125
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-57077",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-57077",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-07-17T13:05:26.689858Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.7,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.2,
"exploitabilityScore": 2.5
}
]
},
"affected": [
{
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"affectedData": [
{
"repo": "https://github.com/toddr/YAML-Syck",
"vendor": "TODDR",
"product": "YAML::Syck",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "1.47",
"versionType": "custom"
}
],
"packageName": "YAML-Syck",
"programFiles": [
"token.c"
],
"collectionURL": "https://cpan.org/modules",
"defaultStatus": "unaffected",
"programRoutines": [
{
"name": "newline_len"
},
{
"name": "is_newline"
}
]
}
]
}
],
"published": "2026-07-16T22:17:43.650",
"references": [
{
"url": "https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
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{
"url": "https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
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{
"url": "https://www.cve.org/CVERecord?id=CVE-2025-11683",
"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
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"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
"description": [
{
"lang": "en",
"value": "CWE-125"
}
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],
"descriptions": [
{
"lang": "en",
"value": "YAML::Syck versions before 1.47 for Perl allow an out-of-bounds read via an unbounded newline scan in newline_len.\n\nIn the bundled libsyck newline_len and is_newline dereference the scan pointer, and the following byte for a \"\\r\\n\" pair, with no NUL-terminator or bounds check. During block-scalar lexing at a document boundary the scan runs one byte past the heap lexer buffer. This is an incomplete fix of CVE-2025-11683, on a lexer path the earlier fix did not cover.\n\nAny caller that runs Load or LoadFile on an untrusted document with a block scalar at a document boundary reaches the over-read."
}
],
"lastModified": "2026-07-17T15:07:41.947",
"sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}