What is CVE-2025-12781?

CVE-2025-12781 is a security advisory published by Microsoft Security Response Center (MSRC) with Medium severity. base64.b64decode() always accepts "+/" characters, despite setting altchars

Which CVE IDs does CVE-2025-12781 cover?

CVE-2025-12781 covers the following CVE IDs: CVE-2025-12781. Each CVE has its own detail page on EchelonGraph Pulse with the synthesized EG score.

What is the CVSS v3 score of CVE-2025-12781?

CVE-2025-12781 has a CVSS v3 base score of 5.3, published by Microsoft Security Response Center (MSRC).

Which products are affected by CVE-2025-12781?

CVE-2025-12781 affects 1 product, including: azl3 python-py 1.11.0-1 on Azure Linux 3.0.

CVE-2025-12781MediumCVSS 5.3

base64.b64decode() always accepts "+/" characters, despite setting altchars

Vendor

Microsoft Security Response Center (MSRC)

Published

October 21, 2026

Last Modified

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🔗 CVE IDs covered (1)

CVE-2025-12781 →

🎯 Affected products1

azl3 python-py 1.11.0-1 on Azure Linux 3.0

✅ Remediation

KBRelease Notes (Security Update)

🔗 References (2)

advisoryhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-12781
referencehttps://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade