{"id":"GHSA-cw26-7653-2rp5","summary":"exiftool-vendored vulnerable to argument injection via newline characters in tag names","details":"### Impact\n\n`exiftool-vendored` starts ExifTool in `-stay_open True -@ -` mode, where arguments are read from stdin one per line. In affected versions, several caller-supplied strings were interpolated into ExifTool arguments without rejecting line delimiters. A newline or carriage return inside one of those strings could split a single intended argument into multiple ExifTool arguments, allowing argument injection. The fix also rejects NUL bytes as unsafe control characters.\n\nApplications that pass attacker-controlled strings to affected APIs may allow an attacker to make ExifTool read files accessible to the ExifTool process, or write output to attacker-chosen file system paths accessible to that process. No remote code execution has been demonstrated.\n\nThe reported write-path issue is caused by unsanitized tag **keys**. Tag **values** passed to `ExifTool#write` are not affected, because `WriteTask` already encodes whitespace characters in values (e.g. `\\n` -\u003e `
`) before transmission.\n\nConfirmed affected inputs:\n\n- **Tag-name arguments / tag keys** — keys of the `tags` object passed to `ExifTool#write`; entries of the `retain` option to `ExifTool#deleteAllTags`; entries of the `numericTags` option to `ExifTool#read`; the `tagname` argument to `ExifTool#extractBinaryTag` and `#extractBinaryTagToBuffer`.\n- **Filename / path arguments** to `ExifTool#write`, `#read`, `#readRaw`, `#deleteAllTags`, `#rewriteAllTags`, `#extractBinaryTag`, `#extractBinaryTagToBuffer`, and the binary-extraction convenience methods `#extractJpgFromRaw`, `#extractPreview`, and `#extractThumbnail`. `path.resolve()` does not strip newlines, so an application that accepts attacker-controlled filenames containing newline characters was vulnerable.\n- **The `imageHashType` option** to `ExifTool#read`. TypeScript types restrict this to a literal union, but JS callers or callers with weakened type checking could reach the sink.\n\nApplications that only pass hardcoded strings for tag names, options, and filenames are not affected.\n\n### Patches\n\nFixed in **v35.19.0**. Two layers of defense:\n\n1. **Per-site input validation.** A new `validateTagName` helper rejects any tag-name string containing characters outside the ExifTool tag grammar (letters, digits, `:`, `-`, `_`, and the ExifTool modifiers `*`, `?`, `+`, `#`). Applied at every tag-name interpolation site.\n2. **Defense-in-depth at the command renderer.** `ExifToolTask.renderCommand` now rejects _any_ argument containing `\\r`, `\\n`, or `\\0` before it is sent to the ExifTool process. This catches injection via filename arguments, option values, and any future interpolation site that forgets the per-site validator.\n\n### Workarounds\n\nUpgrade to v35.19.0 or later.\n\nIf upgrading immediately is not possible, reject untrusted strings containing control characters before passing them to the affected APIs. Conservative guard:\n\n```ts\nfunction assertSafeForExifTool(s: string): void {\n  if (typeof s !== \"string\" || /[\\x00-\\x20=\u003c\u003e]/.test(s)) {\n    throw new Error(\"Rejected unsafe string for ExifTool\");\n  }\n}\n```\n\nApply to tag names, `retain` / `numericTags` entries, binary-extraction tag names, filenames, and the `imageHashType` option. This is a denylist and is strictly weaker than the library's internal validator; it is sufficient to block the known PoCs but will accept strings that the library itself now rejects.\n\n### Resources\n\n- ExifTool `-stay_open` / argument-file documentation: https://exiftool.org/exiftool_pod.html#stay_open-FLAG\n- ExifTool tag-name reference: https://exiftool.org/TagNames/\n- CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') — https://cwe.mitre.org/data/definitions/88.html\n\n### Credit\n\n- Reporter: Hank Tam\n- Affiliation: Independent","aliases":["CVE-2026-43893"],"modified":"2026-05-13T14:34:31.407220Z","published":"2026-05-05T19:53:47Z","database_specific":{"nvd_published_at":"2026-05-11T22:22:14Z","github_reviewed":true,"severity":"HIGH","github_reviewed_at":"2026-05-05T19:53:47Z","cwe_ids":["CWE-88"]},"references":[{"type":"WEB","url":"https://github.com/photostructure/exiftool-vendored.js/security/advisories/GHSA-cw26-7653-2rp5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43893"},{"type":"WEB","url":"https://exiftool.org/TagNames"},{"type":"WEB","url":"https://exiftool.org/exiftool_pod.html#stay_open-FLAG"},{"type":"PACKAGE","url":"https://github.com/photostructure/exiftool-vendored.js"}],"affected":[{"package":{"name":"exiftool-vendored","ecosystem":"npm","purl":"pkg:npm/exiftool-vendored"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"35.19.0"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 35.18.0","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-cw26-7653-2rp5/GHSA-cw26-7653-2rp5.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N"}]}