Summary
brace-expansion: DoS via uncontrolled recursion in parseCommaParts causing stack exhaustion
parseCommaParts() can exhaust the native stack and crash the process. There are two distinct ways to trigger it, both reachable from a single untrusted pattern string.
This is the parsing-side counterpart to CVE-2026-14257 / GHSA-mh99-v99m-4gvg. That fix made expand_() iterative and documented a constant-stack-depth guarantee, but parseCommaParts() was left recursive, so the guarantee only held for one of the two parsing paths.
Vector 1 - unbounded recursion on post
parseCommaParts() recursed on the remainder of the string once per brace group:
const postParts = parseCommaParts(post) // unbounded
A brace group containing many comma-separated groups drives one recursion level per group:
expand('{' + '{a},'.repeat(7000) + 'b}')
// RangeError: Maximum call stack size exceeded
About 7,300 repetitions - roughly 29 KB of input - is enough on Node 24; roughly 6,300 (25 KB) on Node 18. The threshold is identical on every affected release line.
Vector 2 - push.apply with an unbounded array
Even with the recursion removed, parseCommaParts() spread whole arrays into an argument list:
p.push.apply(p, postParts)
parts.push.apply(parts, p)
Function.prototype.apply places one argument per element on the stack, so a single large array overflows it. This needs no recursion depth at all - the following reaches a recursion depth of exactly 1:
expand('{{x},' + 'a,'.repeat(125000) + 'b}')
// RangeError: Maximum call stack size exceeded
Threshold is about 124,300 repetitions (~249 KB). This vector was not part of the original report; it was found while verifying the fix. A patch that only de-recurses but keeps push.apply leaves a working denial of service behind.
Why max and maxLength do not help
Both crashes happen during parsing, before any expansion. The payloads produce one result per group, so output size grows linearly with input and is never the limiter. expand(payload, { max: 1, maxLength: 1 }) still overflows.
Not a regression
5.0.8 and 5.0.9 overflow at the same repetition count, so the gap predates the recent advisories; those fixes simply did not reach it. Verified affected on 1.1.18, 2.1.4, 3.0.6, 5.0.8 and 5.0.9, all at an identical threshold.
Severity note
Scored 7.5 High under CVSS 3.1 for consistency with the other availability advisories on this package (GHSA-mh99-v99m-4gvg, GHSA-rgw5-rvv9-x895), which use the same vector. The reporter self-assessed 6.9 Medium under CVSS 4.0 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N).
Credit
Reported by baeseungwon1010, with a working proof of concept and a proposed patch. Vector 2 was identified during maintainer verification.
Impact
Any application that passes an untrusted string to expand() - directly, or through minimatch / glob where it is a user-supplied glob pattern - can be crashed. In Node, a RangeError that the application does not catch terminates the process, so a server that globs user input is exposed to remote unauthenticated denial of service.
minimatch's own MAX_PATTERN_LENGTH cap (65,536) does not help against vector 1: the overflow threshold sits well below it. Confirmed on minimatch 10.2.6 - a 64,003-byte pattern passes the length check and overflows both minimatch.braceExpand() and new minimatch.Minimatch().
This is an availability-only issue. No code execution and no data exposure.
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
CVE-2026-102276 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.0.10, 3.0.7, 2.1.5, 1.1.19); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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parseCommaParts() is rewritten as a loop that carries the partial part across chunks, and every array append uses an element-by-element loop rather than push.apply. The redundant if (!str) return [''] guard is dropped - the loop returns [''] for the empty string on its own.
Equivalence of the old and new implementations was checked by differential testing: exhaustive over every string of {, }, ,, a up to length 7 plus 300,000 random inputs - 322,000 cases, zero mismatches.
Frequently Asked Questions
- What is CVE-2026-102276? CVE-2026-102276 is a high-severity uncontrolled resource consumption vulnerability in brace-expansion (npm), affecting versions >= 4.0.0, < 5.0.10. It is fixed in 5.0.10, 3.0.7, 2.1.5, 1.1.19. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- How severe is CVE-2026-102276? CVE-2026-102276 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of brace-expansion are affected by CVE-2026-102276? brace-expansion (npm) versions >= 4.0.0, < 5.0.10 is affected.
- Is there a fix for CVE-2026-102276? Yes. CVE-2026-102276 is fixed in 5.0.10, 3.0.7, 2.1.5, 1.1.19. Upgrade to this version or later.
- Is CVE-2026-102276 exploitable, and should I be worried? Whether CVE-2026-102276 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-102276 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-102276?
- Upgrade
brace-expansionto 5.0.10 or later - Upgrade
brace-expansionto 3.0.7 or later - Upgrade
brace-expansionto 2.1.5 or later - Upgrade
brace-expansionto 1.1.19 or later
- Upgrade