CVE-2026-6878: ByteDance verl grader.py math_equal sandbox

Severity: medium (CVSS 5.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-23 · updated 2026-10-26
Weakness: CWE-264

Description

A vulnerability was identified in ByteDance verl up to 0.7.0. Affected is the function math_equal of the file prime_math/grader.py. The manipulation leads to sandbox issue. It is possible to initiate the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.

Affected products

ByteDance verl: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 (+1)

References

https://github.com/zast-ai/vulnerability-reports/blob/main/bytedance/verl_rce.md
https://vuldb.com/submit/795257
https://vuldb.com/vuln/359040
https://vuldb.com/vuln/359040/cti

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