CVE-2026-97701
Zulip is an open-source team collaboration tool.
Impact
Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, the authenticated POST /messages/render endpoint renders the content parameter without enforcing the normal message length limit used by message send and edit operations. An authenticated user can submit Markdown up to the server body-size limit, causing disproportionate backend CPU consumption, and repeated or concurrent requests can degrade Markdown rendering performance or backend availability for other users. This issue is fixed in version 12.2.
An attacker can exploit this over the network, with a regular user account, without any action by a user. If it succeeds: high risk of outages.
Affected products
| Product | Affected versions |
|---|---|
| Zulip Server | through 12.1 |
Versions were read from the advisory text. No structured product data has been published for this record yet.
Weakness classification
References
- NVD record
- CVE.org record
- https://github.com/zulip/zulip/commit/31773c77c501391ede0fa8ec727f39508664e0ae
- https://github.com/zulip/zulip/commit/4d94dd2ee6337a4b3351694dd314a45d3fe11031
- https://github.com/zulip/zulip/pull/39913
- https://github.com/zulip/zulip/releases/tag/12.2
- https://github.com/zulip/zulip/security/advisories/GHSA-m257-w4r5-5rmf
- https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-12-2