Description
@casl/ability 6.7.5 before 7.0.2 contains a prototype pollution vulnerability in rulesToFields() that allows attackers to modify inherited builtins via dotted condition keys. Attackers controlling rule conditions can supply keys like 'toString.call' to alter shared builtin functions process-wide, causing denial of service for the Node.js process.
References5
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 4.0
-
6.0
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 33 · as of 10 November 2026
- CWE
- CWE-1321
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.