BoxLite: Timeout Bypass Vulnerability

published 2026-05-29 5 mo ago modified 2026-09-10 1 mo ago also GHSA-xjhv-pp2r-6f82 , PYSEC-2026-2400 , EUVD-2026-36197

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

Boxlite is a sandbox service that allows users to create lightweight virtual machines (Boxes) and launch OCI containers within them to run untrusted code. In versions 0.8.2 and prior, Boxlite allows users to configure a timeout for services running inside the virtual machine. When the timeout is triggered, Boxlite sends a signal to kill the process. However, instead of using the uncatchable SIGKILL signal, Boxlite uses the catchable SIGALRM signal. Malicious code running inside the sandbox can exploit this vulnerability to continue running after the timeout is triggered, leading to resource exhaustion within the virtual machine and affecting the availability of the Boxlite service. This issue has been patched via commit 28159fc.

Patch / fix

links 1

github.com/boxlite-ai/boxlite@28159fc commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-11)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/boxlite-ai/boxlite/security/advisories/GHSA-xjhv-pp2r-6f82 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
OSV	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
pypi	boxlite	<=0.8.2	no fix listed

Affected products

boxlite-ai boxlite

Classification

Weakness

CWE-404 Improper Resource Shutdown or Release

References

github.com /boxlite-ai/boxlite/commit/28159fc5b6b6fd5037e18a58fc4644c882e3c581
web
github.com /boxlite-ai/boxlite/security/advisories/GHSA-xjhv-pp2r-6f82
exploit, web
nvd.nist.gov /vuln/detail/CVE-2026-47213
advisory
github.com /boxlite-ai/boxlite
package
pypi.org /project/boxlite
package
github.com /advisories/GHSA-xjhv-pp2r-6f82
advisory

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary