CVE-2025-8194: Python Software Foundation CPython · Infinite Loop
Affects Python Software Foundation CPythonSource CVE Database V5
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubpython/cpythonpkg:github/python/cpythonOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A third-party mitigation patch is available and can be applied after importing the tarfile module as a temporary fix. Users should monitor the official Python advisories for an official fix. Until then, applying the provided patch mitigates the infinite loop condition.
Description
CVE-2025-8194 is a high severity vulnerability in the Python Software Foundation's CPython implementation affecting the tarfile module. The flaw causes the TarFile extraction and entry enumeration APIs to enter an infinite loop when processing tar archives with negative offsets. This results in deadlock during parsing of maliciously crafted tar files. The vulnerability affects specific CPython versions including 3.10.0 through 3.14.0a1. No official patch is listed, but a mitigation patch is available as a third-party workaround.
References
- github.com/python/cpython/issues/130577 (opens in a new tab)
- github.com/python/cpython/pull/137027 (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/ZULLF3IZ726XP5EY7XJ7YIN3K5MDYR2D/ (opens in a new tab)
- github.com/python/cpython/commit/7040aa54f14676938970e10c5f74ea93cd56aa38 (opens in a new tab)
- github.com/python/cpython/commit/cdae923ffe187d6ef916c0f665a31249619193fe (opens in a new tab)
- gist.github.com/sethmlarson/1716ac5b82b73dbcbf23ad2eff8b33e1 (opens in a new tab)
- github.com/python/cpython/commit/c9d9f78feb1467e73fd29356c040bde1c104f29f (opens in a new tab)
- github.com/python/cpython/commit/fbc2a0ca9ac8aff6887f8ddf79b87b4510277227 (opens in a new tab)
- github.com/python/cpython/commit/57f5981d6260ed21266e0c26951b8564cc252bc2 (opens in a new tab)
- github.com/python/cpython/commit/73f03e4808206f71eb6b92c579505a220942ef19 (opens in a new tab)
- github.com/python/cpython/commit/b4ec17488eedec36d3c05fec127df71c0071f6cb (opens in a new tab)
- openwall.com/lists/oss-security/2025/07/28/1 (opens in a new tab)
- openwall.com/lists/oss-security/2025/07/28/2 (opens in a new tab)