CVE-2026-33672Picomatch: Method Injection in POSIX Character Classes causes incorrect Glob Matching
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Picomatch is a glob matcher written JavaScript. Versions prior to 4.0.4, 3.0.2, and 2.3.2 are vulnerable to a method injection vulnerability affecting 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. The issue does not enable remote code execution, but it can cause security-relevant logic errors in applications that rely on glob matching for filtering, validation, or access control. All users of affected `picomatch` versions that process untrusted or user-controlled glob patterns are potentially impacted. This issue is fixed in picomatch 4.0.4, 3.0.2 and 2.3.2. Users should upgrade to one of these versions or later, depending on their supported release line. If upgrading is not immediately possible, avoid passing untrusted glob patterns to picomatch. Possible mitigations include sanitizing or rejecting untrusted glob patterns, especially those containing POSIX character classes like `[[:...:]]`; avoiding the use of POSIX bracket expressions if user input is involved; and manually patching the library by modifying `POSIX_REGEX_SOURCE` to use a null prototype.
- CVSS
- 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-1321
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Analyzed
- Record last updated
- Mar 27, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
micromatch picomatch micromatch:picomatch (from the name) | from 4.0.0, < 4.0.4; from 3.0.0, < 3.0.2; before 2.3.2 | CNA record |
jonschlinkert picomatch jonschlinkert:picomatch | before 2.3.2; from 3.0.0 before 3.0.2; from 4.0.0 before 4.0.4 | NVD |
References
- https://github.com/micromatch/picomatch/security/advisories/GHSA-3v7f-55p6-f55px-refsource-confirm, patch, vendor-advisory
- https://github.com/micromatch/picomatch/commit/4516eb521f13a46b2fe1a1d2c9ef6b20ddc0e903x-refsource-misc, patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.