CVE-2021-3426: Debian Linux

Medium severity, CVSS 5.7. EPSS: 1.9% chance of exploitation in the next 30 days.

There's a flaw in Python 3's pydoc. A local or adjacent attacker who discovers or is able to convince another local or adjacent user to start a pydoc server could access the server and use it to disclose sensitive information belonging to the other user that they would not normally be able to access. The highest risk of this flaw is to data confidentiality. This flaw affects Python versions before 3.8.9, Python versions before 3.9.3 and Python versions before 3.10.0a7.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Netapp Cloud Backup: affected versions not specified
• Netapp Ontap Select Deploy Administration Utility: affected versions not specified
• Netapp Snapcenter: affected versions not specified
• Oracle Communications Cloud Native Core Binding Support Function: version 1.10.0 only
• Oracle ZFS Storage Appliance Kit: version 8.8 only
• Python Python: before 2.7.18 (fixed in 2.7.18); from 3.6.0, before 3.6.13 (fixed in 3.6.13); from 3.7.0, before 3.7.10 (fixed in 3.7.10); from 3.8.0, before 3.8.8 (fixed in 3.8.8); from 3.9.0, before 3.9.3 (fixed in 3.9.3); version 3.10.0 only
• Red Hat Enterprise Linux: version 8.0 only
• Red Hat Software Collections: affected versions not specified

Published 2021-05-20. Last modified 2026-06-17.