{"id":"GHSA-h4fr-cmh5-qr62","kind":"vulnerability","aliases":["GHSA-h4fr-cmh5-qr62"],"related":[],"title":"Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root","description":"### Impact\n\nFallow expands some globs from the analyzed repository on disk. Before 3.34.0, a segment such as `.*`, `.?` or `..*` in such a glob also matched the special `..` entry. The `glob` crate tests `..` against a segment that starts with a literal `.`. Fallow validates plugin glob patterns and refuses absolute paths and `..` segments, but these segments passed that validation.\n\nThe attacker controls the repository content. The attacker must also be able to read the Fallow output, for example a CI log or a pull request comment. Then the attacker can learn if a file or directory exists in the parent of the project root:\n\n- A plugin `fileExists` detection pattern such as `.*/marker.json` made the plugin active when `marker.json` existed in the parent directory.\n- An external plugin `configPatterns` or `alwaysUsed` pattern could match a config file in the parent directory. When the plugin was active and declared `toolingDependencies`, the tooling detection credited the related dev dependency. An unused dependency finding could then disappear, and `--trace-dependency` printed the outside path.\n- `fallow plugin-check` reported `path_exists: true` for a seeded entry that matched only in the parent directory.\n\nFallow tested only that these paths exist. It did not read or print the content of a file outside the project root through these globs.\n\nThe Jest, Vitest and Rstest project globs had the same `.*` problem, and the Jest and Vitest ones also read file content. GHSA-jfwm-3p3c-6hx5 describes that case.\n\n### Patches\n\nFixed in 3.34.0. Fallow now rewrites a leading `.` in a wildcard segment to `[.]` before it expands the glob on disk. `[.]` matches the same hidden files and directories inside the project root. The `glob` crate does not test `..` against it.\n\n### Workarounds\n\nRun Fallow only on repositories that you trust. Before you run Fallow on another repository, check the `detection`, `configPatterns` and `alwaysUsed` patterns of its plugin files.","summary":"Before 3.34.0, Fallow's glob expansion let a segment like `.*` match the parent-directory entry `..`, so a malicious repository could check whether files outside the project root exist. The attacker learns only existence (and a dependency path in trace output), not file contents, and must be able to read Fallow's output.","severity":"low","cvss":3.3,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"fallow","fixed":["3.34.0"],"affected":"< 3.34.0","ecosystem":"npm"},{"name":"@fallow-cli/fallow-node","fixed":["3.34.0"],"affected":"< 3.34.0","ecosystem":"npm"},{"name":"fallow-cli","fixed":["3.34.0"],"affected":"< 3.34.0","ecosystem":"cargo"},{"name":"fallow-config","fixed":["3.34.0"],"affected":"< 3.34.0","ecosystem":"cargo"},{"name":"fallow-core","fixed":["3.34.0"],"affected":"< 3.34.0","ecosystem":"cargo"}],"ecosystems":["cargo","npm"],"tags":["cargo","ci","cwe-22","fallow","npm","package","pull-request-analysis"],"not_affected_if":["fixed-version","no-untrusted-plugin-files","trusted-repos-only"],"how_to_check":"- Run `fallow --version` (or check the `fallow` entry in `package-lock.json` / `Cargo.lock`) and confirm it is below `3.34.0`.\n- Check whether the repositories you analyze with Fallow include untrusted plugin files whose `detection`, `configPatterns` or `alwaysUsed` patterns contain `.*`, `.?` or `..*`.","fix":"- Upgrade `fallow` and `@fallow-cli/fallow-node` to `3.34.0`.\n- Upgrade `fallow-cli`, `fallow-config` and `fallow-core` crates to `3.34.0`.\n- Until upgraded, run Fallow only on repositories you trust.","status":"open","published_at":"2026-10-23T21:58:16+00:00","first_seen_at":"2026-10-23T22:05:18+00:00","triaged_at":"2026-10-25T04:45:47+00:00","updated_at":"2026-10-25T04:45:47+00:00","category":"package","confidence":0.85,"triage":{"at":"2026-10-25T04:45:47Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade `fallow` and `@fallow-cli/fallow-node` to `3.34.0`.\n- Upgrade `fallow-cli`, `fallow-config` and `fallow-core` crates to `3.34.0`.\n- Until upgraded, run Fallow only on repositories you trust.","reach":"local","title":"Fallow: wildcard globs let a repository probe files in the parent directory","impact":"low","summary":"Before 3.34.0, Fallow's glob expansion let a segment like `.*` match the parent-directory entry `..`, so a malicious repository could check whether files outside the project root exist. The attacker learns only existence (and a dependency path in trace output), not file contents, and must be able to read Fallow's output.","category":"package","nicknames":[],"who_cares":["fallow","npm","cargo","ci","pull-request-analysis"],"confidence":0.85,"needs_auth":"no","worst_case":"attacker learns whether files exist in parent directory","analyst_note":"","how_to_check":"- Run `fallow --version` (or check the `fallow` entry in `package-lock.json` / `Cargo.lock`) and confirm it is below `3.34.0`.\n- Check whether the repositories you analyze with Fallow include untrusted plugin files whose `detection`, `configPatterns` or `alwaysUsed` patterns contain `.*`, `.?` or `..*`.","needs_analyst":false,"not_affected_if":["fixed-version","trusted-repos-only","no-untrusted-plugin-files"],"who_is_affected":"Teams that run Fallow in CI or on pull requests against repositories they do not fully control, where an outside contributor could add plugin files with wildcard glob patterns and read the Fallow output. Teams that only analyze their own trusted code have low exposure. Jest, Vitest and Rstest project globs share the same flaw, and the Jest and Vitest variant can also read file content (see GHSA-jfwm-3p3c-6hx5).","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000766,"input_tokens":4063,"output_tokens":719,"severity_before":"low"},"analyst_status":null,"analyst_note":null,"search":"'-22':47B '/fallow-node':34A '/marker.json':216C '3.34.0':56B,120C,351C '3p3c':343C '6hx5':344C 'abl':102B,175C 'absolut':154C 'activ':220C,248C 'also':130C,173C,336C 'alwaysus':233C,409C 'analysi':54B 'analyz':7A,115C 'anoth':402C 'attack':85B,165C,171C,193C 'cargo':44B 'case':347C 'check':76B,278C,404C 'ci':45B,184C 'cli':33A,37A 'cmh5':23A,28A 'comment':190C 'config':40A,238C 'configpattern':231C,407C 'content':98B,169C,308C,339C 'control':166C 'core':43A 'could':75B,235C,264C 'crate':137C,382C 'credit':255C 'cwe':46B 'declar':250C 'depend':91B,259C,262C,270C 'describ':345C 'detect':212C,254C,406C 'dev':258C 'directori':69B,200C,227C,243C,293C,375C 'disappear':266C 'disk':118C,368C 'entri':70B,134C,286C 'exampl':182C 'exist':83B,88B,201C,223C,281C,300C 'expand':110C,364C 'expans':60B 'extern':229C 'fallow':1A,10A,30A,32A,36A,39A,42A,48B,57B,105B,109C,147C,179C,275C,294C,352C,390C,400C 'fallow-cli':31A,35A 'fallow-config':38A 'fallow-core':41A 'file':78B,97B,198C,239C,311C,338C,373C,414C 'fileexist':211C 'find':263C 'fix':349C 'ghsa':21A,26A,341C 'ghsa-h4fr-cmh5-qr62':20A,25A 'ghsa-jfwm-3p3c-6hx5':340C 'glob':3A,59B,112C,129C,136C,150C,318C,325C,366C,381C 'h4fr':22A,27A 'hidden':372C 'impact':108C 'insid':376C 'jest':320C,332C 'jfwm':342C 'lead':356C 'learn':86B,195C 'let':5A,61B 'like':64B 'liter':146C 'log':185C 'made':217C 'make':9A 'malici':73B 'marker.json':222C 'match':65B,131C,236C,288C,369C 'must':100B,172C 'npm':49B 'one':335C 'output':95B,107B,180C 'outsid':79B,273C,312C 'packag':50B 'parent':15A,68B,204C,226C,242C,292C 'parent-directori':67B 'pass':161C 'patch':348C 'path':12A,92B,155C,274C,280C,299C 'pattern':151C,213C,234C,410C 'plugin':149C,210C,219C,230C,246C,277C,413C 'plugin-check':276C 'print':271C,306C 'problem':329C 'project':18A,81B,207C,314C,324C,378C 'pull':52B,188C 'pull-request-analysi':51B 'qr62':24A,29A 'read':104B,177C,304C,337C 'refus':153C 'relat':257C 'report':279C 'repositori':8A,74B,116C,168C,393C,403C 'request':53B,189C 'rewrit':354C 'root':19A,82B,208C,315C,379C 'rstest':323C 'run':389C,399C 'seed':285C 'segment':4A,63B,122C,141C,157C,160C,360C 'special':133C 'start':143C 'test':11A,138C,295C,385C 'tool':253C 'toolingdepend':251C 'trace':94B,269C 'trace-depend':268C 'true':282C 'trust':396C 'unus':261C 'valid':148C,163C 'vitest':321C,334C 'whether':77B 'wildcard':359C 'workaround':388C","nicknames":[],"mitigations":[],"who_affected":"Teams that run Fallow in CI or on pull requests against repositories they do not fully control, where an outside contributor could add plugin files with wildcard glob patterns and read the Fallow output. Teams that only analyze their own trusted code have low exposure. Jest, Vitest and Rstest project globs share the same flaw, and the Jest and Vitest variant can also read file content (see GHSA-jfwm-3p3c-6hx5).","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T21:58:16+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","cvss_by":"GitHub","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-h4fr-cmh5-qr62","url":"https://github.com/advisories/GHSA-h4fr-cmh5-qr62","severity":"low","published_at":"2026-10-23T21:58:16+00:00","modified_at":"2026-10-23T21:58:17+00:00","first_seen_at":"2026-10-23T22:05:18+00:00","fetched_at":"2026-10-23T22:05:18+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}