CVE-2026-3446: Base64 decoding stops at first padded quad by default

Published Apr 10, 2026
·
Updated

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 Software

1 affected component
Python Software Foundation CPython

Event History

Apr 10, 2026
CVE Published
via MITRE·06:17 PM
Data Sourced
via MITRE·06:17 PM
Description
Data Sourced
via NVD·07:16 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2026-3446?

CVE-2026-3446 has a medium severity score of 6.

2

How do I fix CVE-2026-3446?

To mitigate CVE-2026-3446, ensure you are using the latest version of Python where the issue is resolved.

3

What is the risk associated with CVE-2026-3446?

CVE-2026-3446 has a risk classification of 33, indicating potential data processing vulnerabilities.

4

What functions are affected by CVE-2026-3446?

CVE-2026-3446 affects the base64.b64decode() function and related decoding methods.

5

How does CVE-2026-3446 affect data processing?

CVE-2026-3446 allows for data to be improperly accepted and processed if it stops decoding at the first padded quad.

Contact

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