Vulnerability Database

309,364

Total vulnerabilities in the database

CVE-2021-41115

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, or main.

  • Published: Oct 7, 2021
  • Updated: Nov 16, 2025
  • CVE: CVE-2021-41115
  • Severity: Low
  • Exploit:

CVSS v3:

  • Severity: Low
  • Score: 4.3
  • AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS v2:

  • Severity: Low
  • Score: 4
  • AV:N/AC:L/Au:S/C:N/I:N/A:P