{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-04T16:55:16.006","vulnerabilities":[{"cve":{"id":"CVE-2021-41115","sourceIdentifier":"security-advisories@github.com","published":"2021-10-07T23:15:08.027","lastModified":"2024-11-21T06:25:30.013","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Zulip is an open source team chat server. In affected versions Zulip allows organization administrators on a server to configure \"linkifiers\" that automatically create links from messages that users send, detected via arbitrary regular expressions. Malicious organization administrators could subject the server to a denial-of-service via regular expression complexity attacks; most simply, by configuring a quadratic-time regular expression in a linkifier, and sending messages that exploited it. A regular expression attempted to parse the user-provided regexes to verify that they were safe from ReDoS -- this was both insufficient, as well as _itself_ subject to ReDoS if the organization administrator entered a sufficiently complex invalid regex. Affected users should [upgrade to the just-released Zulip 4.7](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-to-a-release), or [`main`](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository)."},{"lang":"es","value":"Zulip es un servidor de chat de equipo de código abierto. En las versiones afectadas, Zulip permite a los administradores de la organización en un servidor configurar \"linkifiers\" que crean automáticamente enlaces a partir de los mensajes que envían los usuarios, detectados por medio de expresiones regulares arbitrarias. Los administradores de organizaciones maliciosos podían someter al servidor a una denegación de servicio por medio de ataques de complejidad de expresiones regulares; más sencillo, al configurar una expresión regular de tiempo cuadrático en un enlazador, y enviando mensajes que la explotaran. Una expresión regular intentaba analizar las expresiones regulares proporcionadas por el usuario para verificar que estaban a salvo de ReDoS - esto era insuficiente, así como _suficiente para someter al servidor a ReDoS si el administrador de la organización introducía una expresión regular no válida suficientemente compleja. Los usuarios afectados deberían [actualizar a la recién estrenada Zulip versión 4.7](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-to-a-release), o [`main`](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository)"}],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","baseScore":4.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW"},"exploitabilityScore":2.8,"impactScore":1.4},{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":6.5,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":3.6}],"cvssMetricV2":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"2.0","vectorString":"AV:N/AC:L/Au:S/C:N/I:N/A:P","baseScore":4.0,"accessVector":"NETWORK","accessComplexity":"LOW","authentication":"SINGLE","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"PARTIAL"},"baseSeverity":"MEDIUM","exploitabilityScore":8.0,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}]},"weaknesses":[{"source":"security-advisories@github.com","type":"Secondary","description":[{"lang":"en","value":"CWE-400"},{"lang":"en","value":"CWE-1333"}]},{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-1333"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:*","versionEndExcluding":"4.7","matchCriteriaId":"C12C5D8B-FC65-4A14-B843-106963C0AEA8"}]}]}],"references":[{"url":"https://github.com/zulip/zulip/commit/e2d303c1bb5f538d17dc3d9134bc8858bdece781","source":"security-advisories@github.com","tags":["Patch","Third Party Advisory"]},{"url":"https://github.com/zulip/zulip/security/advisories/GHSA-4h36-mqfq-42jg","source":"security-advisories@github.com","tags":["Patch","Third Party Advisory"]},{"url":"https://securitylab.github.com/advisories/GHSL-2021-118-zulip-zulip/","source":"security-advisories@github.com","tags":["Exploit","Third Party Advisory"]},{"url":"https://github.com/zulip/zulip/commit/e2d303c1bb5f538d17dc3d9134bc8858bdece781","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch","Third Party Advisory"]},{"url":"https://github.com/zulip/zulip/security/advisories/GHSA-4h36-mqfq-42jg","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Patch","Third Party Advisory"]},{"url":"https://securitylab.github.com/advisories/GHSL-2021-118-zulip-zulip/","source":"af854a3a-2127-422b-91ae-364da2661108","tags":["Exploit","Third Party Advisory"]}]}}]}