CVE-2021-41115

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Summary

CVECVE-2021-41115
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-10-07 23:15:00 UTC
Updated2023-07-17 15:18:00 UTC
DescriptionZulip 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).

Risk And Classification

Problem Types: CWE-1333

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Zulip Zulip All All All All

References

ReferenceSourceLinkTags
CVE-2021-41115: Use re2 for user-supplied linkifier patterns. · zulip/zulip@e2d303c · GitHub MISC github.com
Regular expression denial-of-service in linkifiers · Advisory · zulip/zulip · GitHub CONFIRM github.com
GitHub Security Lab | Securing the world’s software, together MISC securitylab.github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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