CVE-2026-3446
Base64 decoding stops at first padded quad by default
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.
INFO
Published Date :
April 10, 2026, 7:16 p.m.
Last Modified :
April 10, 2026, 7:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-3446
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 28c92f92-d60d-412d-b760-e73465c3df22 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Call base64.b64decode() with validate=True.
- Ensure all base64 data is fully validated.
- Update applications using base64 decoding.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-3446.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-3446 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-3446
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-3446 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-3446 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Apr. 10, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added Reference https://github.com/python/cpython/commit/1f9958f909c1b41a4ffc0b613ef8ec8fa5e7c474 Added Reference https://github.com/python/cpython/commit/4561f6418a691b3e89aef0901f53fe0dfb7f7c0e Added Reference https://github.com/python/cpython/commit/e31c55121620189a0d1a07b689762d8ca9c1b7fa Added Reference https://github.com/python/cpython/issues/145264 Added Reference https://github.com/python/cpython/pull/145267 Added Reference https://mail.python.org/archives/list/[email protected]/thread/F5ZT5ICGJ6CKXVUJ34YBVY7WOZ5SHG53/