CVE-2025-8194Loop with Unreachable Exit Condition (Infinite Loop)
NVDCVSS scored by cna@python.org
Vulnerability Summary
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
This vulnerability can be mitigated by including the following patch after importing the “tarfile” module: https://gist.github.com/sethmlarson/1716ac5b82b73dbcbf23ad2eff8b33e1
CVSS v3.1 Base Metrics — Score 7.5 (HIGH)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HAttack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
Affected & Patched Versions
Not provided by NVD for this CVE.
No patched version published yet
Until a fix ships, reduce exposure:
- Restrict access to the affected service or interface to trusted networks.
- Disable the affected feature if you do not need it.
- Watch the vendor advisory for a firmware or software update.
What to do
Plan remediation soon. No exploitation is confirmed yet, but the severity is high.
- Check whether you run the affected product and which version.
- No patched version is listed yet. Limit access to the affected service to trusted networks, and disable the feature if you can.
- Subscribe to the vendor advisory so you learn when a fix ships.
Timeline
- Jul 28, 2025Published
- Jul 31, 2026Record last modified
Score, severity and exploitation changes are tracked from the day Watchtower started logging them.
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External References
- Referencehttps://gist.github.com/sethmlarson/1716ac5b82b73dbcbf23ad2eff8b33e1
- Patchhttps://github.com/python/cpython/commit/57f5981d6260ed21266e0c26951b8564cc252bc2
- Patchhttps://github.com/python/cpython/commit/7040aa54f14676938970e10c5f74ea93cd56aa38
- Patchhttps://github.com/python/cpython/commit/73f03e4808206f71eb6b92c579505a220942ef19
- Patchhttps://github.com/python/cpython/commit/b4ec17488eedec36d3c05fec127df71c0071f6cb
- Patchhttps://github.com/python/cpython/commit/c9d9f78feb1467e73fd29356c040bde1c104f29f
- Patchhttps://github.com/python/cpython/commit/cdae923ffe187d6ef916c0f665a31249619193fe
- Patchhttps://github.com/python/cpython/commit/fbc2a0ca9ac8aff6887f8ddf79b87b4510277227
- Issue Trackinghttps://github.com/python/cpython/issues/130577
- Patchhttps://github.com/python/cpython/pull/137027
- Referencehttps://mail.python.org/archives/list/security-announce@python.org/thread/ZULLF3IZ726XP5EY7XJ7YIN3K5MDYR2D/
- Advisoryhttp://www.openwall.com/lists/oss-security/2025/07/28/1
- Advisoryhttp://www.openwall.com/lists/oss-security/2025/07/28/2
Data last checked: Nov 13, 2026 13:08 (site time)