Mattermost doesn't validate the X-Requested-With header on the burn-on-read reveal endpoint
Exact source revision recorded 24 Oct 2026 13:19:41 UTC. It does not establish the source's current position. Latest evidence.
osv · GHSA-xvcx-mgpc-5xh3
PublishedMattermost versions 11.5.x <= 11.5.1, 11.4.x <= 11.4.3 fail to validate the X-Requested-With header on the burn-on-read reveal endpoint which allows an authenticated channel member to force the reveal of a burn-on-read message without recipient consent via a crafted Markdown image tag.. Mattermost Advisory ID: MMSA-2026-00636
- Source published
- 18 May 2026 09:31:48 UTC
- Source modified
- 25 Jun 2026 23:11:08 UTC
- Observed here
- 24 Oct 2026 13:19:41 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
Original source record · Cite this exact observation · Complete original publisher JSON
This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.
CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Publisher rating · MODERATE