CVE-2026-4867

{"id": "CVE-2026-4867", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "published": "2026-03-26T17:16:42.983", "references": [{"url": "https://blakeembrey.com/posts/2024-09-web-redos", "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}, {"url": "https://cna.openjsf.org/security-advisories.html", "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}, {"url": "https://github.com/advisories/GHSA-9wv6-86v2-598j", "source": "ce714d77-add3-4f53-aff5-83d477b104bb"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "ce714d77-add3-4f53-aff5-83d477b104bb", "description": [{"lang": "en", "value": "CWE-1333"}]}], "descriptions": [{"lang": "en", "value": "Impact:\n\nA bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in path-to-regexp@0.1.12 only prevents ambiguity for two parameters. With three or more, the generated lookahead does not block single separator characters, so capture groups overlap and cause catastrophic backtracking.\n\nPatches:\n\nUpgrade to path-to-regexp@0.1.13\n\nCustom regex patterns in route definitions (e.g., /:a-:b([^-/]+)-:c([^-/]+)) are not affected because they override the default capture group.\n\nWorkarounds:\n\nAll versions can be patched by providing a custom regular expression for parameters after the first in a single segment. As long as the custom regular expression does not match the text before the parameter, you will be safe. For example, change /:a-:b-:c to /:a-:b([^-/]+)-:c([^-/]+).\n\nIf paths cannot be rewritten and versions cannot be upgraded, another alternative is to limit the URL length."}, {"lang": "es", "value": "Impacto:\n\nSe genera una expresi\u00f3n regular incorrecta cada vez que se tienen tres o m\u00e1s par\u00e1metros dentro de un \u00fanico segmento, separados por algo que no sea un punto (.). Por ejemplo, /:a-:b-:c o /:a-:b-:c-:d. La protecci\u00f3n contra retroceso a\u00f1adida en path-to-regexp@0.1.12 solo previene la ambig\u00fcedad para dos par\u00e1metros. Con tres o m\u00e1s, el 'lookahead' generado no bloquea los caracteres separadores individuales, por lo que los grupos de captura se superponen y causan un retroceso catastr\u00f3fico.\n\nParches:\n\nActualizar a path-to-regexp@0.1.13\n\nLos patrones de expresiones regulares personalizados en las definiciones de ruta (por ejemplo, /:a-:b([^-/]+)-:c([^-/]+)) no se ven afectados porque anulan el grupo de captura predeterminado.\n\nSoluciones provisionales:\n\nTodas las versiones pueden ser parcheadas proporcionando una expresi\u00f3n regular personalizada para los par\u00e1metros despu\u00e9s del primero en un \u00fanico segmento. Siempre y cuando la expresi\u00f3n regular personalizada no coincida con el texto anterior al par\u00e1metro, estar\u00e1 seguro. Por ejemplo, cambie /:a-:b-:c a /:a-:b([^-/]+)-:c([^-/]+).\n\nSi las rutas no pueden ser reescritas y las versiones no pueden ser actualizadas, otra alternativa es limitar la longitud de la URL."}], "lastModified": "2026-03-30T13:26:50.827", "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb"}