The tar implementation would process tar archives with negative offsets without error, resulting in an infinite loop
Source GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 4 Nov 2026, 17:55 UTC
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
Weaponized: 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 4 Nov 2026.
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 patch is available via a code workaround that overrides the TarInfo._block method to raise an InvalidHeaderError on negative offsets. Users should apply this patch after importing the tarfile module to prevent infinite loops. No official vendor patch or advisory is provided in the data; thus, this workaround is the recommended mitigation.
Description
A vulnerability in the CPython tarfile module allows processing of tar archives with negative offsets without error, causing an infinite loop and deadlock during parsing of crafted archives. This can lead to denial of service by hanging the application. A mitigation patch involves overriding the _block method to raise an error on negative offsets.
References
- nvd.nist.gov/vuln/detail/CVE-2025-8194 (opens in a new tab)
- github.com/python/cpython/issues/130577 (opens in a new tab)
- github.com/python/cpython/pull/137027 (opens in a new tab)
- github.com/python/cpython/commit/57f5981d6260ed21266e0c26951b8564cc252bc2 (opens in a new tab)
- github.com/python/cpython/commit/7040aa54f14676938970e10c5f74ea93cd56aa38 (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)
- github.com/python/cpython/commit/c9d9f78feb1467e73fd29356c040bde1c104f29f (opens in a new tab)
- github.com/python/cpython/commit/cdae923ffe187d6ef916c0f665a31249619193fe (opens in a new tab)
- github.com/python/cpython/commit/fbc2a0ca9ac8aff6887f8ddf79b87b4510277227 (opens in a new tab)
- gist.github.com/sethmlarson/1716ac5b82b73dbcbf23ad2eff8b33e1 (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/ZULLF3IZ726XP5EY7XJ7YIN3K5MDYR2D (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)