CVE-2026-33948

Full vulnerability record from the local CVENow database.

Description

jq is a command-line JSON processor. Commits before 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contain a vulnerability where CLI input parsing allows validation bypass via embedded NUL bytes. When reading JSON from files or stdin, jq uses strlen() to determine buffer length instead of the actual byte count from fgets(), causing it to truncate input at the first NUL byte and parse only the preceding prefix. This enables an attacker to craft input with a benign JSON prefix before a NUL byte followed by malicious trailing data, where jq validates only the prefix as valid JSON while silently discarding the suffix. Workflows relying on jq to validate untrusted JSON before forwarding it to downstream consumers are susceptible to parser differential attacks, as those consumers may process the full input including the malicious trailing bytes. This issue has been patched by commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b.

Severity

LOW

CVSS score

2.9 (v4.0)

Vulnerability status

Analyzed

Source identifier

[email protected]

Published

2026-04-14 00:16:06.867000

Last modified

2026-10-26 22:10:00.163000

View original CVE JSON

{
  "id": "CVE-2026-33948",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-14T00:16:06.867",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Analyzed",
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      "value": "jq is a command-line JSON processor. Commits before 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contain a vulnerability where CLI input parsing allows validation bypass via embedded NUL bytes. When reading JSON from files or stdin, jq uses strlen() to determine buffer length instead of the actual byte count from fgets(), causing it to truncate input at the first NUL byte and parse only the preceding prefix. This enables an attacker to craft input with a benign JSON prefix before a NUL byte followed by malicious trailing data, where jq validates only the prefix as valid JSON while silently discarding the suffix. Workflows relying on jq to validate untrusted JSON before forwarding it to downstream consumers are susceptible to parser differential attacks, as those consumers may process the full input including the malicious trailing bytes. This issue has been patched by commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b."
    },
    {
      "lang": "es",
      "value": "jq es un procesador JSON de línea de comandos. Commits anteriores a 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contienen una vulnerabilidad donde el análisis de entrada CLI permite eludir la validación a través de bytes NUL incrustados. Al leer JSON de archivos o stdin, jq usa strlen() para determinar la longitud del búfer en lugar del recuento real de bytes de fgets(), lo que hace que trunque la entrada en el primer byte NUL y analice solo el prefijo precedente. Esto permite a un atacante crear una entrada con un prefijo JSON benigno antes de un byte NUL seguido de datos maliciosos al final, donde jq valida solo el prefijo como JSON válido mientras descarta silenciosamente el sufijo. Los flujos de trabajo que dependen de jq para validar JSON no confiable antes de reenviarlo a consumidores posteriores son susceptibles a ataques diferenciales de analizador, ya que esos consumidores pueden procesar la entrada completa, incluidos los bytes maliciosos finales. Este problema ha sido parcheado por el commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b."
    }
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  "affected": [
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          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
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}