CVEsbeam-cloudCVE-2026-120308Published Nov 1, 12:51 · Updated Nov 1, 12:51 UTC
9.9
CriticalCVSS 3.1 · from JFROG
CVE-2026-120308

Beta9 host filesystem exposure via volume path traversal

github.com/beam-cloud/beta9 · Path traversal · CWE-22
Affectedgithub.com/beam-cloud/beta9, github.com/beam-cloud/beta9
FixUpdate to 0.1.776, 0.1.756 or newer
PublishedNov 1, 12:51 · JFROG
ScoredNov 1 · 9.9 · JFROG
Exploit code publicNone known · checked 21:18 UTC
ExploitedNone known · CISA KEV checked 22:09 UTC

What we know

No known exploitation. CISA KEV, checked 22:09 UTC.
No public exploit code known. Exploit-DB, Metasploit, Nuclei, checked 21:18 UTC.
An attacker needs network access and an account. CVSS: network, low privileges.
A successful attack can read and change data and take the service down. CVSS: high impact on confidentiality, integrity and availability.

Description

A Beta9 tenant can attach a volume when deploying a function, endpoint, or task queue. The gateway builds the host path by joining the shared volumes root, the workspace name, and the volume identifier from the stub configuration. Nothing checks that the identifier names a volume that workspace owns. Parent-directory segments in the identifier collapse the joined path to the worker's filesystem root, and the worker bind-mounts that path into the sandbox read-write unless the volume was explicitly marked read-only. A tenant with a workspace token can therefore read and write the worker's files, including other tenants' volumes stored on that machine. Confirmed against gateway 0.1.769 and worker 0.1.745. Fixed in gateway 0.1.776 and worker 0.1.756: volume identifiers and mount paths are validated before a mount is built, including for stubs saved before the check existed, and the gateway rejects a volume that does not exist or is not owned by the workspace.

From JFROG

Affected and fixed versions

ProductAffectedFixed ingithub.com/beam-cloud/beta9before 0.1.7760.1.776github.com/beam-cloud/beta9before 0.1.7560.1.756

Exploit code

Exploit-DBnone knownMetasploitnone knownNucleinone known

References

Beta9 repository · github.comproductHandle sandbox edge cases (fix pull request) · github.compatchFix commit a28bf12 · github.compatchgateway-0.1.776 · github.comrelease notesworker-0.1.756 · github.comrelease notesgateway-0.1.769 (confirmed affected) · github.comtechnical descriptionworker-0.1.745 (confirmed affected) · github.comtechnical description

Other CVEs in github.com/beam-cloud/beta9

All 2 →
9.9Beta9 container escape via unvalidated sandbox file paths · CVE-2026-120307Nov 19.9Beta9 build sandbox escape via chroot-only isolation · CVE-2026-120306Nov 1