// For flags

CVE-2025-8194

Tarfile infinite loop during parsing with negative member offset

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Attend
*SSVC
Descriptions

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

Existe un defecto en el módulo "tarfile" de CPython que afecta a las API de extracción y enumeración de entradas de "TarFile". La implementación de tar procesaba archivos tar con desplazamientos negativos sin errores, lo que resultaba en un bucle infinito y un bloqueo durante el análisis de archivos tar manipulados con fines maliciosos. Esta vulnerabilidad se puede mitigar incluyendo el siguiente parche después de importar el módulo "tarfile": import tarfile def _block_patched(self, count): if count < 0: # pragma: no cover raise tarfile.InvalidHeaderError("invalid offset") return _block_patched._orig_block(self, count) _block_patched._orig_block = tarfile.TarInfo._block tarfile.TarInfo._block = _block_patched

This update for python39 fixes the following issues. Fixed denial of service caused by tar archives with negative offsets.

*Credits: Alexander Urieles, Seth Larson, Ethan Furman, Steve Dower
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:Attend
Exploitation
None
Automatable
Yes
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2025-07-25 CVE Reserved
  • 2025-07-28 CVE Published
  • 2025-08-08 EPSS Updated
  • 2025-08-14 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Python Software Foundation
Search vendor "Python Software Foundation"
 CPython
Search vendor "Python Software Foundation" for product "CPython"
 < 3.13.6
Search vendor "Python Software Foundation" for product "CPython" and version " < 3.13.6"
en
Affected