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Response snapshot Oct 27, 2026, 01:11 UTC

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VulnerabilityGHSA-h4fr-cmh5-qr62

Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root

Fallow 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 `.`.

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: fallow: 3.34.0; @fallow-cli/fallow-node: 3.34.0; fallow-cli: 3.34.0; fallow-config: 3.34.0; fallow-core: 3.34.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-h4fr-cmh5-qr62 (opens a new tab)

What happened

### Impact

Fallow 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.

The 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:

- A plugin `fileExists` detection pattern such as `.*/marker.json` made the plugin active when `marker.json` existed in the parent directory. - 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.

Continue reading

An unused dependency finding could then disappear, and `--trace-dependency` printed the outside path. - `fallow plugin-check` reported `path_exists: true` for a seeded entry that matched only in the parent directory.

Fallow tested only that these paths exist. It did not read or print the content of a file outside the project root through these globs.

The 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.

### Patches

Fixed 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.

### Workarounds

Run 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.

Affected package ranges reported by GitHub: fallow: < 3.34.0 @fallow-cli/fallow-node: < 3.34.0 fallow-cli: < 3.34.0 fallow-config: < 3.34.0 fallow-core: < 3.34.0

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-h4fr-cmh5-qr62 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h4fr-cmh5-qr62, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 23). Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root. https://kevwire.com/record/GHSA-h4fr-cmh5-qr62

MLA

"Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root." KEVWire, 23 Oct. 2026, kevwire.com/record/GHSA-h4fr-cmh5-qr62.

Chicago

KEVWire. "Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root." Last modified October 23, 2026. https://kevwire.com/record/GHSA-h4fr-cmh5-qr62.

Evidence summary (plain text)

Fallow: A `.*` glob segment let an analyzed repository make Fallow test paths in the parent of the project root (Oct 23, 2026).
Fallow 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.

The 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:
Sources:
GitHub-reviewed advisory GHSA-h4fr-cmh5-qr62: https://github.com/advisories/GHSA-h4fr-cmh5-qr62
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: GHSA-h4fr-cmh5-qr62.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 20:55 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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