CVE-2026-6594

brikcss merge prototype pollution

A vulnerability was determined in brikcss merge up to 1.3.0. This affects an unknown part. Executing a manipulation of the argument __proto__/constructor.prototype/prototype can lead to improperly controlled modification of object prototype attributes. The attack may be performed from remote. The vendor was contacted early about this disclosure but did not respond in any way.

Affected

brikcss · merge

CVSS v4.0 VULDB

6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/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

CVSS v4.0 GitHub

6.9 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS v3.1 VULDB

7.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v2.0 VULDB

7.5 HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P

EPSS

0.56% chance of exploitation in the next 30 days, 45th percentile

Published

2026-04-20

Proof-of-concept exploits (1)

• sudo-secure/security-research/blob/main/brikcss-merge/prototype-pollution/PoC.md1★ · 2026-04-23

Security advisories

• advisories/GHSA-3jc6-6r48-v6qf

References

• CVE Record
• NVD entry

Related

• CVE-2026-5472
• CVE-2026-6486
• CVE-2026-6492
• CVE-2026-6621