{"id":"DEBIAN-CVE-2026-23950","details":"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., `ß` 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 `ß` and `ss` are different), conflicting paths do not have their order properly preserved under filesystems that ignore Unicode normalization (e.g., APFS (in which `ß` 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.","modified":"2026-09-14T17:01:02.294319107Z","published":"2026-01-20T01:15:57.870Z","upstream":["CVE-2026-23950"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-23950"}],"affected":[{"package":{"name":"node-tar","ecosystem":"Debian:12","purl":"pkg:deb/debian/node-tar?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.1.13+~cs7.0.5-1","6.1.13+~cs7.0.5-1+deb12u1","6.1.13+~cs7.0.5-2","6.1.13+~cs7.0.5-3","6.1.13+~cs7.0.5-4","6.2.1+ds1+~cs6.1.13-1","6.2.1+ds1+~cs6.1.13-10","6.2.1+ds1+~cs6.1.13-11","6.2.1+ds1+~cs6.1.13-2","6.2.1+ds1+~cs6.1.13-3","6.2.1+ds1+~cs6.1.13-4","6.2.1+ds1+~cs6.1.13-5","6.2.1+ds1+~cs6.1.13-6","6.2.1+ds1+~cs6.1.13-7","6.2.1+ds1+~cs6.1.13-8","6.2.1+ds1+~cs6.1.13-9","6.2.1+~cs7.0.8-1","7.5.16+~4.0.1-1","7.5.16+~4.0.1-2","7.5.19+~4.0.1-1","7.5.19+~4.0.1-2","7.5.22+~4.0.1-1"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-23950.json"}},{"package":{"name":"node-tar","ecosystem":"Debian:13","purl":"pkg:deb/debian/node-tar?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.2.1+~cs7.0.8-1+deb13u1"}]}],"versions":["6.2.1+~cs7.0.8-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-23950.json"}},{"package":{"name":"node-tar","ecosystem":"Debian:14","purl":"pkg:deb/debian/node-tar?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.2.1+ds1+~cs6.1.13-7"}]}],"versions":["6.2.1+ds1+~cs6.1.13-1","6.2.1+ds1+~cs6.1.13-2","6.2.1+ds1+~cs6.1.13-3","6.2.1+ds1+~cs6.1.13-4","6.2.1+ds1+~cs6.1.13-5","6.2.1+ds1+~cs6.1.13-6","6.2.1+~cs7.0.8-1"],"ecosystem_specific":{"urgency":"unimportant"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-23950.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}