CVE-2026-33054: Mesop has a Path Traversal utilizing `FileStateSessionBackend` leads to Application Denial of Service and File Write/Deletion

March 18, 2026 (updated March 20, 2026)

A Path Traversal vulnerability allows any user (or attacker) supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation.

References

github.com/advisories/GHSA-8qvf-mr4w-9x2c
github.com/mesop-dev/mesop
github.com/mesop-dev/mesop/commit/c6b382f363b73ac32c402a2db3aadc7784f66a5b
github.com/mesop-dev/mesop/releases/tag/v1.2.3
github.com/mesop-dev/mesop/security/advisories/GHSA-8qvf-mr4w-9x2c
nvd.nist.gov/vuln/detail/CVE-2026-33054

Code Behaviors & Features

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