CVE-2021-41115

{
  "id": "CVE-2021-41115",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:S/C:N/I:N/A:P",
          "authentication": "SINGLE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
          "integrityImpact": "NONE",
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          "attackComplexity": "LOW",
          "availabilityImpact": "LOW",
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.8
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  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "zulip",
          "product": "zulip",
          "versions": [
            {
              "status": "affected",
              "version": "< 4.7"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-10-07T23:15:08.027",
  "references": [
    {
      "url": "https://github.com/zulip/zulip/commit/e2d303c1bb5f538d17dc3d9134bc8858bdece781",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
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    },
    {
      "url": "https://github.com/zulip/zulip/security/advisories/GHSA-4h36-mqfq-42jg",
      "tags": [
        "Patch",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://securitylab.github.com/advisories/GHSL-2021-118-zulip-zulip/",
      "tags": [
        "Exploit",
        "Third Party Advisory"
      ],
      "source": "security-advisories@github.com"
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    {
      "url": "https://github.com/zulip/zulip/commit/e2d303c1bb5f538d17dc3d9134bc8858bdece781",
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        "Third Party Advisory"
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      "tags": [
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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      "tags": [
        "Exploit",
        "Third Party Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-1333"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1333"
        }
      ]
    }
  ],
  "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)"
    }
  ],
  "lastModified": "2026-06-17T04:07:54.053",
  "configurations": [
    {
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        {
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  "sourceIdentifier": "security-advisories@github.com"
}