CVE-2025-12781: base64.b64decode() always accepts "+/" characters, despite setting altchars

Overview

Severity

Medium (CVSS 5.3)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Exploit Status

Not Exploited

Patch Tuesday

2026-Jan

Released

2026-10-21

EPSS Score

0.56% (percentile: 45.9%)

Affected Products (1)

Other

• 21639-17084

Revision History

• 2026-10-21: Information published.