CVE-2026-3446

medium

Description

When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 data.

References

https://mail.python.org/archives/list/[email protected]/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/

https://github.com/python/cpython/pull/145267

https://github.com/python/cpython/issues/145264

https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa

https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e

https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474

Details

Source: Mitre, NVD

Published: 2026-04-10

Updated: 2026-04-10

Risk Information

CVSS v2

Base Score: 6.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: High

CVSS v4

Base Score: 6

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Medium