node-tar has Race Condition in Path Reservations via Unicode Ligature Collisions on macOS APFS_CVE-2026-23950

{
    "lastseen": "",
    "description": "node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3. This is due to an incomplete handling of Unicode path collisions in the `path-reservations` system. On case-insensitive or normalization-insensitive filesystems (such as macOS APFS, In which it has been tested), the library fails to lock colliding paths (e.g., `\u00df` and `ss`), allowing them to be processed in parallel. This bypasses the library's internal concurrency safeguards and permits Symlink Poisoning attacks via race conditions. The library uses a `PathReservations` system to ensure that metadata checks and file operations for the same path are serialized. This prevents race conditions where one entry might clobber another concurrently. This is a Race Condition which enables Arbitrary File Overwrite. This vulnerability affects users and systems using node-tar on macOS (APFS/HFS+). Because of using `NFD` Unicode normalization (in which `\u00df` and `ss` are different), conflicting paths do not have their order properly preserved under filesystems that ignore Unicode normalization (e.g., APFS (in which `\u00df` causes an inode collision with `ss`)). This enables an attacker to circumvent internal parallelization locks (`PathReservations`) using conflicting filenames within a malicious tar archive. The patch in version 7.5.4 updates `path-reservations.js` to use a normalization form that matches the target filesystem's behavior (e.g., `NFKD`), followed by first `toLocaleLowerCase('en')` and then `toLocaleUpperCase('en')`. As a workaround, users who cannot upgrade promptly, and who are programmatically using `node-tar` to extract arbitrary tarball data should filter out all `SymbolicLink` entries (as npm does) to defend against arbitrary file writes via this file system entry name collision issue.",
    "published": "2026-01-20T00:40:48.510Z",
    "modified": "2026-01-20T00:40:48.510Z",
    "type": "cve",
    "title": "node-tar has Race Condition in Path Reservations via Unicode Ligature Collisions on macOS APFS",
    "source": "GitHub_M",
    "references": "https://github.com/isaacs/node-tar/security/advisories/GHSA-r6q2-hw4h-h46w\nhttps://github.com/isaacs/node-tar/commit/3b1abfae650056edfabcbe0a0df5954d390521e6",
    "id": "CVE-2026-23950",
    "bulletinFamily": "",
    "cwe": [
        "CWE-176",
        "CWE-352",
        "CWE-367"
    ],
    "cvelist": null,
    "sourceData": "isaacs node-tar < 7.5.4",
    "sourceHref": "",
    "cvss": {
        "score": 8.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "node-tar",
    "version": "< 7.5.4",
    "vendor": "isaacs",
    "ai_description": "node-tar has a race condition vulnerability in versions up to and including 7.5.3, allowing Symlink Poisoning attacks via Unicode path collisions on case-insensitive filesystems like macOS APFS",
    "ai_severity": "High",
    "ai_vendor": "isaacs",
    "ai_product": "node-tar",
    "ai_version": "< 7.5.4",
    "ai_score": 8.8
}