CVE-2020-13757: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 1.4% chance of exploitation in the next 30 days.

Python-RSA before 4.1 ignores leading '\0' bytes during decryption of ciphertext. This could conceivably have a security-relevant impact, e.g., by helping an attacker to infer that an application uses Python-RSA, or if the length of accepted ciphertext affects application behavior (such as by causing excessive memory allocation).

Affected products

• Canonical Ubuntu Linux: version 14.04 only
• Fedoraproject Fedora: version 31 only; version 32 only
• Python-Rsa Project Python-Rsa: before 4.1 (fixed in 4.1)

Published 2020-06-01. Last modified 2026-06-17.