SB2026081815 - Prototype pollution in Picomatch

Description

This security bulletin contains information about 1 vulnerability.

1) Prototype pollution (CVE-ID: CVE-2026-33672)

CWE-ID: CWE-1321 - Improperly Controlled Modification of Object Prototype Attributes (\'Prototype Pollution\')

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to execute arbitrary JavaScript code.

The method injection vulnerability affects the `POSIX_REGEX_SOURCE` object. Because the object inherits from `Object.prototype`, specially crafted POSIX bracket expressions (e.g., `[[:constructor:]]`) can reference inherited method names. These methods are implicitly converted to strings and injected into the generated regular expression. This leads to incorrect glob matching behavior (integrity impact), where patterns may match unintended filenames.. A remote attacker can pass specially crafted input to the application and perform prototype pollution, which can result in information disclosure or data manipulation.

Remediation

Install update from vendor's website.

References

• https://github.com/micromatch/picomatch/commit/4516eb521f13a46b2fe1a1d2c9ef6b20ddc0e903
• https://github.com/micromatch/picomatch/security/advisories/GHSA-3v7f-55p6-f55p