CVE-2023-22735
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.
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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.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
- Puntuación base: 4.6
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.52%
- Percentil entre todas las CVEs puntuadas: 42
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-436
Referencias
- https://github.com/zulip/zulip/commit/04cf68b45ebb5c03247a0d6453e35ffc175d55da
- https://github.com/zulip/zulip/commit/2f6c5a883e106aa82a570d3d1f243993284b70f3
- https://github.com/zulip/zulip/security/advisories/GHSA-wm83-3764-5wqh
- https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository
- https://github.com/zulip/zulip/commit/04cf68b45ebb5c03247a0d6453e35ffc175d55da
- https://github.com/zulip/zulip/commit/2f6c5a883e106aa82a570d3d1f243993284b70f3
- https://github.com/zulip/zulip/security/advisories/GHSA-wm83-3764-5wqh
- https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository
JSON original (NVD)
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