CVE-2026-43893

描述

### Impact `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. Applications 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. The 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` -> `&#10;`) before transmission. Confirmed affected inputs: - **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`. - **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. - **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. Applications that only pass hardcoded strings for tag names, options, and filenames are not affected. ### Patches Fixed in **v35.19.0**. Two layers of defense: 1. **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. 2. **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. ### Workarounds Upgrade to v35.19.0 or later. If upgrading immediately is not possible, reject untrusted strings containing control characters before passing them to the affected APIs. Conservative guard: ```ts function assertSafeForExifTool(s: string): void { if (typeof s !== "string" || /[\x00-\x20=<>]/.test(s)) { throw new Error("Rejected unsafe string for ExifTool"); } } ``` Apply 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. ### Resources - ExifTool `-stay_open` / argument-file documentation: https://exiftool.org/exiftool_pod.html#stay_open-FLAG - ExifTool tag-name reference: https://exiftool.org/TagNames/ - CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') — https://cwe.mitre.org/data/definitions/88.html ### Credit - Reporter: Hank Tam - Affiliation: Independent