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CVE-2026-6594

brikcss merge prototype pollution

6.9 Medium

CVE-2026-6594 is a medium vulnerability (CVSS 6.9) in Brikcss Merge, published April 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 27th percentile. No source names a fixed version.

What does this mean?
Severity
6.9 MediumCVSS 4.0, CVE List
Exploit chance
0.34%EPSS, 27th percentile
Exploitation
None knownNot on CISA’s or ENISA’s lists
Fixed in
No fix listedNo source names one

Description

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
Low

Exploit likelihood

0.34%Up 0.3 points since Apr 20, 2026
90%50%10%1%

Affected products

Affected packages

Affected packages
PackageAffectedFixed
@brikcss/merge
npm
through 1.3.1None known

What each source reports

CVE List Score used6.9

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.

Record
CVE-2026-6594
CVSS 4.0
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
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:R
CVSS 3.0
7.3 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:X/RL:X/RC:R
CVSS 2.0
7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P/E:ND/RL:ND/RC:UR
Weakness
CWE-1321, CWE-94
Updated
2026-11-02
EUVDEUVD-2026-237426.9

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.

Record
EUVD-2026-23742
CVSS 4.0
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
Updated
2026-11-02
GitHub AdvisoriesGHSA-3jc6-6r48-v6qf6.9

Deep Merge is Vulnerable to Prototype Pollution Through Lack of Sanitization

A Prototype Pollution vulnerability was determined in brikcss merge up to 1.3.0. 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.

Record
GHSA-3jc6-6r48-v6qf
CVSS 4.0
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 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness
CWE-94, CWE-1321
Updated
2026-11-02
NVD6.9

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.

Record
CVE-2026-6594
CVSS 4.0
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 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 2.0
7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness
CWE-94, CWE-1321
Updated
2026-11-02
OSVGHSA-3jc6-6r48-v6qf6.9

Deep Merge is Vulnerable to Prototype Pollution Through Lack of Sanitization

A Prototype Pollution vulnerability was determined in brikcss merge up to 1.3.0. 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.

Record
GHSA-3jc6-6r48-v6qf
CVSS 4.0
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 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Weakness
CWE-1321, CWE-94
Updated
2026-11-02

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

References

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