GHSA-r292-9mhp-454m

node-tar: Uncontrolled recursion in mapHas/filesFilter allows uncatchable stack-overflow DoS via crafted long-path tar with member selection

Published

2026-07-24

Modified

2026-07-24

Sources

github-advisory

Summary

## Summary `node-tar` (npm `tar`) contains an uncontrolled-recursion stack-exhaustion DoS in the internal `mapHas` helper used by `filesFilter`. When a consumer calls `tar.t(...)` or `tar.x(...)` with a non-empty member-selection list, node-tar installs a filter that closes over the recursive `mapHas` (`src/list.ts:33-44`). `mapHas` walks an entry path upward one `path.dirname()` call per recursion **with no segment cap**. A single crafted tar with a GNU-`L` (or PAX-`x`) long-path header can deliver a path of tens of thousands of `/`-separated segments (up to `maxMetaEntrySize` = 1 MiB). The recursion overflows the call stack, throwing an uncatchable `RangeError` that terminates the Node process on async/streaming consumers. ## Root Cause `filesFilter` (`src/list.ts:27-51`) is installed whenever a caller passes a member-selection list (`src/list.ts:119-122`, `src/extract.ts:55-57`). Its filter is invoked at `src/parse.ts:253` (`entry.ignore = entry.ignore || !this.filter(entry.path, entry)`) inside `Parser[CONSUMEHEADER]` — and crucially **outside** the only try/catch in that method (which wraps `new Header` at `src/parse.ts:179-183`). `mapHas` recurses once per path segment with no depth limit. The `Unpack` `maxDepth` guard (`src/unpack.ts:342`, in `[CHECKPATH]`) only runs on the `'entry'` event, which fires *after* `CONSUMEHEADER` has already invoked the filter — so the stack overflows before any depth guard executes. `tar.t` (list) has no `maxDepth` at all. ## Impact Unauthenticated, remotely-triggerable denial of service: a ~188-byte gzip (≈26 KB tar) crashes any service that lists or extracts *selected members* from an untrusted archive (package registries, CI artifact/cache restore, upload processors). On async (`await tar.t(...)`/`tar.x(...)`) and streaming/`pipe` consumers the `RangeError` escapes the promise as an `uncaughtException` and terminates the process — standard defensive `try/catch` around the async call does NOT prevent it. (The synchronous API is catchable; the async/stream paths — the dominant server pattern — are not.) ## Proof of Concept ```js // Build a tar whose single entry has a GNU-L long path of ~12,000 "a/" segments (~26 KB), // gzip it (≈188 bytes), then have a consumer list/extract with member selection: const tar = require('tar'); await tar.t({ file: 'evil.tar.gz', gzip: true }, ['some-member']); // -> RangeError, process exit ``` Empirically reproduced on Node v24.18.0 against built `dist/commonjs` of node-tar 7.5.20: 188-byte gzip → 26,112-byte tar (12,000 segments) → uncaught `RangeError: Maximum call stack size exceeded` → process exit. A control run with no member-selection list (filter not installed) parses cleanly (exit 0), isolating `mapHas` as the sole cause. ## Attack Chain 1. **Entry.** Attacker crafts a tar with a GNU `L` (or PAX `x`) long-path header whose body is `"a/"`×~12000 (~26 KB), followed by a normal file entry. - **Guard:** `maxMetaEntrySize` caps the meta body at 1 MiB (`src/parse.ts:241`). - **Bypass proof:** 26 KB ≪ 1 MiB → accepted (verified: 26 KB archive parsed up to the filter). 2. **Trigger.** Victim service calls `tar.t({file},[sel])` or `tar.x({file,cwd},[sel])` (member selection — a documented, common API). - **Guard:** `Unpack.maxDepth` (default 1024) at `src/unpack.ts:342`; decompression-ratio guard. - **Bypass proof:** `maxDepth` lives in `[CHECKPATH]` on the `'entry'` event, which fires *after* `CONSUMEHEADER`'s filter call — the crash occurs before it (extract exits 1 with default maxDepth). `tar.t` has no maxDepth. Ratio is ~139× (trivial); no total-bytes cap applies to the uncompressed meta body. 3. **Sink.** `this.filter(entry.path)` → `mapHas` recurses once per `/` segment (`src/list.ts:39`). - **Guard:** try/catch in `CONSUMEHEADER`. - **Bypass proof:** the only try/catch wraps `new Header` (`src/parse.ts:179-183`); the `this.filter(...)` call at `src/parse.ts:253` is outside it. The `RangeError` propagates out of the stream writ

Affected packages

Remediation: Upgrade to 7.5.21 or later.

References

• https://github.com/advisories/GHSA-r292-9mhp-454m