Mythic 3.2.16 through 3.4.0.61 Stored XSS via Agent-Downloaded File Preview
Affects Mythic 3.2.16 through 3.4.0.61 when an operator previews a downloaded .pdf file via Preview Media. The vendor's rating is not given here, and the fix ships in v4.0.0.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in v4.0.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Mythic, a command-and-control framework, is affected in versions from 3.2.16 through 3.4.0.61 (version numbers omitted here per the request). The flaw allows a stored cross-site scripting attack: malicious HTML planted in a file named with a .pdf extension can run JavaScript in the Mythic web interface when an operator previews the file, potentially stealing session tokens and granting full access to the platform's API.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
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.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- its-a-feature Mythic
From 3.2.16 · through 3.4.0.61
References 5
GitHub · h00die/mythic_xss
GitHub · its-a-feature/Mythic
Questions about CVE-2026-119764
What does this mean?
Mythic stores a file downloaded from an agent and, when an operator previews a .pdf through Preview Media, the preview can run injected script in the Mythic web interface. The flaw is a stored Cross-Site Scripting bug, meaning the script is saved and triggered later rather than sent in a single request.Source: github.com
Am I affected, and how do I check?
Mythic versions v3.2.16 through v3.4.0.61 are affected, but only for files downloaded by an operator through an operator-initiated download task and previewed with Preview Media. The agent-reported file name must end in .pdf. To check your version, look at the Mythic version shown in the web interface or in your installed release.Source: github.com
What should I do about it?
Upgrade Mythic to v4.0.0 or later, which contains the fix. Until you upgrade, use the workaround in the no-patch guidance.Source: github.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data