Zulip is an open-source team collaboration tool. In versions of zulip prior to commit 2f6c5a8 but after commit 04cf68b users could upload files with arbitrary Content-Type which would be served from the Zulip hostname with Content-Disposition: inline and no Content-Security-Policy header, allowing them to trick other users into executing arbitrary Javascript in the context of the Zulip application. Among other things, this enables session theft. Only deployments which use the S3 storage (not the local-disk storage) are affected, and only deployments which deployed commit 04cf68b45ebb5c03247a0d6453e35ffc175d55da, which has only been in main, not any numbered release. Users affected should upgrade from main again to deploy this fix. Switching from S3 storage to the local-disk storage would nominally mitigate this, but is likely more involved than upgrading to the latest main which addresses the issue.
CVE-2023-22735
This medium-severity CVE scores 4.4 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 47% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.4
- EG Score
- 4.4(medium)
- EPSS
- 40.7%
- KEV
- Not listed
Published
February 7, 2023
Last Modified
November 21, 2024
References (8)
- security-advisories@githubhttps://github.com/zulip/zulip/commit/04cf68b45ebb5c03247a0d6453e35ffc175d55da
- security-advisories@githubhttps://github.com/zulip/zulip/commit/2f6c5a883e106aa82a570d3d1f243993284b70f3
- security-advisories@githubhttps://github.com/zulip/zulip/security/advisories/GHSA-wm83-3764-5wqh
- security-advisories@githubhttps://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository
- af854a3a-2127-422b-91ae-364da2661108https://github.com/zulip/zulip/commit/04cf68b45ebb5c03247a0d6453e35ffc175d55da
- af854a3a-2127-422b-91ae-364da2661108https://github.com/zulip/zulip/commit/2f6c5a883e106aa82a570d3d1f243993284b70f3
- af854a3a-2127-422b-91ae-364da2661108https://github.com/zulip/zulip/security/advisories/GHSA-wm83-3764-5wqh
- af854a3a-2127-422b-91ae-364da2661108https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 47× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 106 total refreshes for this CVE.
- 2026-07-22 14:06 UTCEPSS rescore
- 2026-07-21 15:23 UTCEPSS rescore
- 2026-07-20 17:05 UTCEPSS rescore
- 2026-07-19 14:29 UTCEPSS rescore
- 2026-07-19 14:29 UTCEPSS rescore
- 2026-07-19 02:27 UTCEPSS rescore
- 2026-07-19 02:27 UTCEPSS rescore
- 2026-07-18 10:03 UTCEPSS rescore
- 2026-07-18 10:03 UTCEPSS rescore
- 2026-07-16 17:01 UTCEPSS rescore
- 2026-07-16 17:01 UTCEPSS rescore
- 2026-07-16 06:49 UTCOSV refresh
- 2026-07-15 16:56 UTCEPSS rescore
- 2026-07-15 01:58 UTCEPSS rescore
- 2026-07-15 01:58 UTCEPSS rescore
- 2026-07-13 22:28 UTCEPSS rescore
- 2026-07-13 22:28 UTCEPSS rescore
- 2026-07-13 06:11 UTCEPSS rescore
- 2026-07-12 05:45 UTCEPSS rescore
- 2026-07-12 05:45 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:08 UTCEPSS rescore
- 2026-07-08 15:13 UTCEPSS rescore
- 2026-07-07 13:44 UTCEPSS rescore
Show 75 moreShow fewer
- 2026-07-06 16:26 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-05 02:28 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-02 16:58 UTCEPSS rescore
- 2026-07-01 15:04 UTCEPSS rescore
- 2026-06-30 23:21 UTCEPSS rescore
- 2026-06-29 14:04 UTCEPSS rescore
- 2026-06-28 14:06 UTCEPSS rescore
- 2026-06-28 14:06 UTCEPSS rescore
- 2026-06-28 06:21 UTCOSV refresh
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-27 03:07 UTCEPSS rescore
- 2026-06-25 13:48 UTCEPSS rescore
- 2026-06-25 13:48 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-22 14:24 UTCEPSS rescore
- 2026-06-22 14:24 UTCEPSS rescore
- 2026-06-21 14:55 UTCEPSS rescore
- 2026-06-21 14:55 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-21 01:58 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-19 19:24 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-18 17:51 UTCEPSS rescore
- 2026-06-17 17:51 UTCEPSS rescore
- 2026-06-17 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-16 17:51 UTCEPSS rescore
- 2026-06-15 17:47 UTCEPSS rescore
- 2026-06-14 23:16 UTCEPSS rescore
- 2026-06-13 22:59 UTCEPSS rescore
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-11 13:59 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-10 22:17 UTCEPSS rescore
- 2026-06-10 16:47 UTCOSV refresh
- 2026-06-10 13:21 UTCEPSS rescore
- 2026-06-10 13:21 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-06 13:46 UTCEPSS rescore
- 2026-06-06 13:46 UTCEPSS rescore
- 2026-06-05 22:46 UTCEPSS rescore
- 2026-06-05 22:46 UTCEPSS rescore
- 2026-06-05 22:46 UTCEPSS rescore
- 2026-06-05 06:09 UTCEPSS rescore
- 2026-06-05 06:09 UTCEPSS rescore
- 2026-06-04 13:11 UTCEPSS rescore
- 2026-06-04 13:11 UTCEPSS rescore
- 2026-06-02 20:12 UTCEPSS rescore
- 2026-06-02 20:12 UTCEPSS rescore
- 2026-06-02 20:12 UTCEPSS rescore
- 2026-06-01 13:51 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-29 13:43 UTCEPSS rescore
- 2026-05-29 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
Frequently asked(5)
What is CVE-2023-22735?
When was CVE-2023-22735 disclosed?
Is CVE-2023-22735 actively exploited?
What is the CVSS score of CVE-2023-22735?
How do I remediate CVE-2023-22735?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2023-22735
Is Your Infrastructure Affected by CVE-2023-22735?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.