What’s Vulnerable › Vulnerabilities

CVE-2026-2297: SourcelessFileLoader does not use io.open_code()

• Severity: medium (CVSS 5.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-04 · updated 2026-08-13
• Weakness: CWE-668

Description

The import hook in CPython that handles legacy *.pyc files (SourcelessFileLoader) is incorrectly handled in FileLoader (a base class) and so does not use io.open_code() to read the .pyc files. sys.audit handlers for this audit event therefore do not fire.

Affected products

• Python: before 3.10.21; from 3.11.0 before 3.11.16; from 3.12.0 before 3.12.14; from 3.13.0 before 3.13.13; from 3.14.0 before 3.14.4; from 3.15.0a1 before 3.15.0a7 — fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.13, 3.14.4, 3.15.0a7

How to fix

Upgrade to a fixed version: Python 3.10.21, 3.11.16, 3.12.14, 3.13.13. Check the vendor advisory for mitigations.

References

• https://github.com/python/cpython/commit/482d6f8bdba9da3725d272e8bb4a2d25fb6a603e
• https://github.com/python/cpython/commit/69ddd9bb2cc4bd69b1565647c18659c6a789ccd9
• https://github.com/python/cpython/commit/876858c9f65d9ab656c7fa639f268ce7856d89dd
• https://github.com/python/cpython/commit/a51b1b512de1d56b3714b65628a2eae2b07e535e
• https://github.com/python/cpython/commit/c70adad78caeeea33f92f560ecb93331ca11bf66
• https://github.com/python/cpython/commit/e58e9802b9bec5cdbf48fc9bf1da5f4fda482e86
• https://github.com/python/cpython/issues/145506
• https://github.com/python/cpython/pull/145507
• http://www.openwall.com/lists/oss-security/2026/03/05/6

Get alerted when CVE-2026-2297 or the next vulnerability affects your stack