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6.0 Medium

CVE-2026-3446 When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded…

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.

Affected products and versions

Product Affected versions Fixed in
CPython 3.15 3.15.0a1 → < 3.15.0a8 3.15.0a8
CPython 3.14 3.14.0 → < 3.14.4 3.14.4
CPython 3.13 earliest → < 3.13.13 3.13.13

References

Timeline

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