CVE-2026-97701: zulip · Unthrottled Resource Allocation
Affects zulipSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 12.2 when convenient.
Data as of 4 Nov 2026, 19:30 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 6.5 |
|---|
- Patch
- Available – fixed in 12.2
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Upgrade zulip and zulip/zulip to 12.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| zulipzulip | Affected
| Fixed in
|
GitHubzulip/zulippkg:github/zulip/zulipOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Zulip Server to version 12.2 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.
Description
Zulip Server versions through 12.1 have a vulnerability in the authenticated POST /messages/render endpoint where the content parameter is rendered without enforcing the usual message length limits. This allows an authenticated user to submit large Markdown content up to the server body-size limit, leading to excessive CPU consumption. Repeated or concurrent requests can degrade Markdown rendering performance and backend availability for other users. The issue is fixed in Zulip version 12.2.
References
- github.com/zulip/zulip/security/advisories/GHSA-m257-w4r5-5rmf (opens in a new tab)
- github.com/zulip/zulip/pull/39913 (opens in a new tab)
- github.com/zulip/zulip/commit/31773c77c501391ede0fa8ec727f39508664e0ae (opens in a new tab)
- github.com/zulip/zulip/commit/4d94dd2ee6337a4b3351694dd314a45d3fe11031 (opens in a new tab)
- github.com/zulip/zulip/releases/tag/12.2 (opens in a new tab)
- zulip.readthedocs.io/en/latest/overview/changelog.html (opens in a new tab)