CVE-2026-33750 | brace-expansion: Zero-step sequence causes process hang and memory exhaustion

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13, a brace pattern with a zero step value (e.g., `{1..2..0}`) causes the sequence generation loop to run indefinitely, making the process hang for seconds and allocate heaps of memory. Versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13 fix the issue. As a workaround, sanitize strings passed to `expand()` to ensure a step value of `0` is not used.

Published: 2026-03-27 Last update: 2026-04-22 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33750 is rated Low Risk (28.1/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). 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-2026-33750

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 0.05% 0.02% -0.03%
2 2026-03-28 — 0.05% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33750

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H 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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 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:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-33750

GitHub Security Advisory for CVE-2026-33750

GHSA-f886-m6hf-6m8v · Severity: medium · Ecosystem: npm — brace-expansion: Zero-step sequence causes process hang and memory exhaustion

OS Trackers for CVE-2026-33750

vendor priority summary link
debian not yet assigned CVE-2026-33750 not yet assigned priority: Debian including 1 source packages (node-brace-expansion), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-33750
redhat medium — https://access.redhat.com/security/cve/CVE-2026-33750
ubuntu medium CVE-2026-33750 medium priority: Ubuntu including 1 source packages (node-brace-expansion), 6 status rows across 6 suites (bionic, focal, jammy, noble, questing, upstream): needs-triage 5, released 1. https://ubuntu.com/security/CVE-2026-33750

Affected software / configurations for CVE-2026-33750

Vendor Product Version Raw CPE
juliangruber brace-expansion < 1.1.13 cpe:2.3:a:juliangruber:brace-expansion:*:*:*:*:*:node.js:*:*
juliangruber brace-expansion >= 2.0.0, < 2.0.3 cpe:2.3:a:juliangruber:brace-expansion:*:*:*:*:*:node.js:*:*
juliangruber brace-expansion >= 3.0.0, < 3.0.2 cpe:2.3:a:juliangruber:brace-expansion:*:*:*:*:*:node.js:*:*
juliangruber brace-expansion >= 5.0.0, < 5.0.5 cpe:2.3:a:juliangruber:brace-expansion:*:*:*:*:*:node.js:*:*

References for CVE-2026-33750

URL Tags
https://github.com/juliangruber/brace-expansion/blob/daa71bcb4a30a2df9bcb7f7b8daaf2ab30e5794a/src/index.ts#L107-L113 Patch
https://github.com/juliangruber/brace-expansion/blob/daa71bcb4a30a2df9bcb7f7b8daaf2ab30e5794a/src/index.ts#L184 Patch
https://github.com/juliangruber/brace-expansion/commit/311ac0d54994158c0a384e286a7d6cbb17ee8ed5 Patch
https://github.com/juliangruber/brace-expansion/commit/7fd684f89fdde3549563d0a6522226a9189472a2 Patch
https://github.com/juliangruber/brace-expansion/commit/b9cacd9e55e7a1fa588fe4b7bb1159d52f1d902a Patch
https://github.com/juliangruber/brace-expansion/issues/98 Issue Tracking
https://github.com/juliangruber/brace-expansion/pull/95 Issue Tracking Patch
https://github.com/juliangruber/brace-expansion/pull/96 Issue Tracking Patch
https://github.com/juliangruber/brace-expansion/pull/97 Issue Tracking Patch
https://github.com/juliangruber/brace-expansion/security/advisories/GHSA-f886-m6hf-6m8v Mitigation Vendor Advisory
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