CVE-2026-119764
Mythic 3.2.16 through 3.4.0.61 Stored XSS via Agent-Downloaded File Preview
Mythic 3.2.16 through 3.4.0.61 contains a stored cross-site scripting vulnerability that allows attackers controlling target endpoint files to run JavaScript in the Mythic UI origin by planting HTML in .pdf-named files. When an operator downloads the file and clicks Preview Media, content-sniffed HTML from /direct/view renders same-origin, stealing localStorage JWTs for full GraphQL and REST access.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Mythic its-a-feature its-a-feature/Mythic
github |
≥ 3.2.16; ≤ 3.4.0.61 (affected, custom)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 7.4 high |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 6.8 medium |
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N | CNA: VulnCheck |
Exploit evidence
- https://github.com/h00die/mythic_xss
exploit · ADP: CISA-ADP
References
- https://github.com/h00die/mythic_xssCNA: VulnCheck · third-party-advisory
- https://github.com/its-a-feature/Mythic/commit/f06b3ed2d1de6577744cc0b3146966c625685859CNA: VulnCheck · patch
- https://github.com/its-a-feature/Mythic/blob/33a46d7db7e237458d7e20e7d3cfefef8112e590/MythicReactUI/src/components/pages/Callbacks/ResponseDisplayMedia.js#L335-L336CNA: VulnCheck · technical-description
- https://github.com/its-a-feature/MythicCNA: VulnCheck · product
- https://www.vulncheck.com/advisories/mythic-3.2.16-through-3.4.0.61-stored-xss-via-agent-downloaded-file-previewCNA: VulnCheck · third-party-advisory
- https://github.com/h00die/mythic_xssADP: CISA-ADP · exploit
For agents and automation
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