---
title: "CVE-2026-1774: CASL Ability is Vulnerable to Prototype Pollution"
url: https://erroneo.us/security/cve/CVE-2026-1774/
description: "CVE-2026-1774 (@casl/ability (npm)): CASL Ability, versions 2.4.0 through 6.7.4, contains a prototype pollution vulnerability."
type: vulnerability-record
section: "Security Digest"
date_published: 2026-02-10
date_modified: 2026-02-11
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-1774"
kev: false
cvss: 9.8
epss: 0.00715
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-1774: CASL Ability is Vulnerable to Prototype Pollution

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.7% , percentile 53: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 53% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes @casl/ability (npm) >= 2.4.0, <= 6.7.4, fixed in 6.7.5 . Check your lockfile, including transitive dependencies.

## What it is

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

## Affected packages

- npm `@casl/ability` >= 2.4.0, <= 6.7.4 → fixed: 6.7.5

## Affected products (CVE record)

- CASL Ability CASL Ability: 2.4.0 <= 6.7.4

## Severity

- CISA-ADP CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.71% probability of exploitation activity in the next 30 days; percentile 53.

## Sources

- [GitHub Advisory GHSA-x9vf-53q3-cvx6](https://github.com/advisories/GHSA-x9vf-53q3-cvx6)
- [CVE.org record CVE-2026-1774](https://www.cve.org/CVERecord?id=CVE-2026-1774)
- [NVD entry CVE-2026-1774](https://nvd.nist.gov/vuln/detail/CVE-2026-1774)
- [github.com](https://github.com/stalniy/casl/tree/master/packages/casl-ability)
- [cwe.mitre.org](https://cwe.mitre.org/data/definitions/1321.html)
- [developer.mozilla.org](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/Prototype_pollution)
- [kb.cert.org](https://www.kb.cert.org/vuls/id/458422)
- [github.com](https://github.com/stalniy/casl/pull/1093)
- [github.com](https://github.com/stalniy/casl/commit/39da920ec1dfadf3655e28bd0389e960ac6871f4)

---
Source page: https://erroneo.us/security/cve/CVE-2026-1774/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt