CVE-2026-6878
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA sandbox vulnerability exists in ByteDance verl up to version 0.7.0 within the math_equal function in prime_math/grader.py. The function likely fails to properly validate or sanitize mathematical expressions or inputs, allowing an attacker to escape the sandbox environment. The public availability of the exploit increases risk.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check if ByteDance verl is installedRun 'pip show verl' or check your Python environment for the verl packageAffected if verl is installed and version is 0.7.0 or lower
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Verify the verl version numberRun 'pip show verl' and look for the Version field, or import verl and print(verl.__version__)Affected if Version is 0.7.0 or any version up to 0.7.0 (e.g., 0.6.0, 0.5.0, etc.)
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Locate the prime_math/grader.py moduleFind the verl installation directory (pip show -f verl) and navigate to prime_math/grader.pyAffected if The file exists in the installation and contains a math_equal function
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Inspect math_equal function usageSearch codebases that import verl for calls to math_equal or similar math evaluation functions from the grader moduleAffected if Code actively uses or calls the math_equal function from prime_math.grader
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Check sandbox configuration for math evaluationReview verl configuration files, environment variables, or code that sets sandbox policies around mathematical expression evaluationAffected if Sandbox is not explicitly configured or is disabled for the math_equal function, or if arbitrary code execution is permitted within the math evaluation context
You are affected if verl version 0.7.0 or lower is installed AND the math_equal function in prime_math/grader.py is being used in your environment.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade verl beyond version 0.7.0 when a patch is available; alternatively, implement additional input validation and stricter sandboxing controls around the math_equal function to prevent escape attempts.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-6878 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-6878 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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