CVE-2026-3446

EUVD-2026-21545
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
PSFCNA
6 MEDIUM
NETWORK
HIGH
LOW
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
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
pythoncpython
𝑥
< 3.13.13
CNA
pythoncpython
3.14.0 ≤
𝑥
< 3.14.4
CNA
References
https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474
https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e
https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa
https://github.com/python/cpython/issues/145264
https://github.com/python/cpython/pull/145267
https://mail.python.org/archives/list/security-announce@python.org/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/