CVE-2025-8194: Tarfile infinite loop during parsing with negative member offset

There is a defect in the CPython “tarfile” module affecting the “TarFile” extraction and entry enumeration APIs. The tar implementation would process tar archives with negative offsets without error, resulting in an infinite loop and deadlock during the parsing of maliciously crafted tar archives.

This vulnerability can be mitigated by including the following patch after importing the “tarfile” module:

import tarfile

def blockpatched(self, count): if count < 0: # pragma: no cover raise tarfile.InvalidHeaderError("invalid offset") return blockpatched.origblock(self, count)

blockpatched.origblock = tarfile.TarInfo.block tarfile.TarInfo.block = blockpatched

— Red Hat

There is a defect in the CPython “tarfile” module affecting the “TarFile” extraction and entry enumeration APIs. The tar implementation would process tar archives with negative offsets without error, resulting in an infinite loop and deadlock during the parsing of maliciously crafted tar archives.

This vulnerability can be mitigated by including the following patch after importing the “tarfile” module:  https://gist.github.com/sethmlarson/1716ac5b82b73dbcbf23ad2eff8b33e1

— NVD