CVE-2026-33672 | Picomatch: Method Injection in POSIX Character Classes causes incorrect Glob Matching

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.

Published: 2026-03-26 Last update: 2026-04-01 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-33672 is rated Low Risk (26.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33672

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-21 0.16% 0.05% -0.11%
2 2026-04-01 0.12% 0.16% +0.04%
3 2026-03-27 0.12%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33672

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 [email protected]

Weakness enumeration for CVE-2026-33672

GitHub Security Advisory for CVE-2026-33672

GHSA-3v7f-55p6-f55p · Severity: medium · Ecosystem: npm — Picomatch: Method Injection in POSIX Character Classes causes incorrect Glob Matching

OS Trackers for CVE-2026-33672

vendor priority summary link
debian not yet assigned CVE-2026-33672 not yet assigned priority: Debian including 1 source packages (node-anymatch), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-33672
redhat medium https://access.redhat.com/security/cve/CVE-2026-33672
ubuntu medium CVE-2026-33672 medium priority: Ubuntu including 1 source packages (node-anymatch), 6 status rows across 6 suites (bionic, focal, jammy, noble, questing, upstream): needs-triage 5, released 1. https://ubuntu.com/security/CVE-2026-33672

Affected software / configurations for CVE-2026-33672

Vendor Product Version Raw CPE
jonschlinkert picomatch < 2.3.2 cpe:2.3:a:jonschlinkert:picomatch:*:*:*:*:*:node.js:*:*
jonschlinkert picomatch >= 3.0.0, < 3.0.2 cpe:2.3:a:jonschlinkert:picomatch:*:*:*:*:*:node.js:*:*
jonschlinkert picomatch >= 4.0.0, < 4.0.4 cpe:2.3:a:jonschlinkert:picomatch:*:*:*:*:*:node.js:*:*

References for CVE-2026-33672

cvelogic Threat Intelligence