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CVE-2026-97701Zulip: Missing content-length limit on POST /messages/render allows denial-of-service via oversized requests
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.
6.5 MEDIUMEPSS 0.43%Not in KEVNVD: Awaiting Analysis
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 6.5 | MEDIUM | 3.1GitHub_M (CNA) | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Details
- CVE ID
- CVE-2026-97701
- Status
- Awaiting Analysis
- Assigner (CNA)
- GitHub_M
- Published
- Nov 4, 2026
- Last modified
- 2026-11-06 21:29 UTC
- Weaknesses
- CWE-770 · Allocation of Resources Without Limits or Throttling
Affected Products
As published by the CNA in the CVE record.
zulipzulip1 version range
- < 12.2
References
- github.com https://github.com/zulip/zulip/commit/31773c77c501391ede0fa8ec727f39508664e0ae
- github.com https://github.com/zulip/zulip/commit/4d94dd2ee6337a4b3351694dd314a45d3fe11031
- github.com https://github.com/zulip/zulip/pull/39913
- github.com https://github.com/zulip/zulip/releases/tag/12.2
- github.com https://github.com/zulip/zulip/security/advisories/GHSA-m257-w4r5-5rmf
- zulip.readthedocs.io https://zulip.readthedocs.io/en/latest/overview/changelog.html#zulip-server-12-2