How severe is CVE-2025-59840?

CVE-2025-59840 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-59840?

CVE-2025-59840 affects the following packages: vega (npm), vega-expression (npm), vega-interpreter (npm), vega-interpreter (npm), vega-expression (npm). Ecosystems affected: npm.

How do I fix CVE-2025-59840?

Update vega to 6.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59840 is resolved across your whole dependency graph.

How do I detect CVE-2025-59840 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vega. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2025-59840 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-59840?

O3 pinpoints whether CVE-2025-59840 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2025-59840 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-59840 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-59840?

CVE-2025-59840 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 25th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-59840?

CVE-2025-59840 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-59840 published, and has it been updated?

CVE-2025-59840 was published on November 13, 2025 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-59840: vega (High 8.1)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk25th percentile+0.30%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

5 pkgs affected

📦vega📦vega-expression📦vega-interpreter📦vega-interpreter📦vega-expression

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.

Description

Vega is a visualization grammar, a declarative format for creating, saving, and sharing interactive visualization designs. In Vega prior to version 6.2.0, applications meeting 2 conditions are at risk of arbitrary JavaScript code execution, even if "safe mode" expressionInterpreter is used. They are vulnerable if they use vega in an application that attaches vega library and a vega.View instance similar to the Vega Editor to the global window and if they allow user-defined Vega JSON definitions (vs JSON that was is only provided through source code). Patches are available in the following Vega applications. If using the latest Vega line (6.x), upgrade to vega 6.2.0 / vega-expression 6.1.0 / vega-interpreter 2.2.1 (if using AST evaluator mode). If using Vega in a non-ESM environment, upgrade to vega-expression 5.2.1 / 1.2.1 (if using AST evaluator mode). Some workarounds are available. Do not attach vega View instances to global variables, and do not attach vega to the global window. These practices of attaching the vega library and View instances may be convenient for debugging, but should not be used in production or in any situation where vega/vega-lite definitions could be provided by untrusted parties.

Affected Packages

5 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`vega`	all versions	6.2.0
📦npm	`vega-expression`	≥ 6.0.0&&< 6.1.0	6.1.0
📦npm	`vega-interpreter`	≥ 2.0.0&&< 2.2.1	2.2.1
📦npm	`vega-interpreter`	all versions	1.2.1
📦npm	`vega-expression`	all versions	5.2.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vega. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update vega to 6.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59840 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-59840 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-59840. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Vega is a visualization grammar, a declarative format for creating, saving, and sharing interactive visualization designs. In Vega prior to version 6.2.0, applications meeting 2 conditions are at risk of arbitrary JavaScript code execution, even if "safe mode" expressionInterpreter is used. They are vulnerable if they use `vega` in an application that attaches `vega` library and a `vega.View` instance similar to the Vega Editor to the global `window` and if they allow user-defined Vega `JSON` definitions (vs JSON that was is only provided through source code). Patches are available in the foll

O3 Security · Impact-Aware SCA

Is CVE-2025-59840 in your dependencies?

O3 detects CVE-2025-59840 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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CVE-2025-59840