# CVE-2020-13757: python3-rsa: Python-RSA before 4.1 ignores leading '\0' bytes during decryption of ciphertext

CVE-2020-13757 is fixed in 2 products on 1 platform, first by python-rsa 3.4.2-1ubuntu0.1~esm1, released June 1, 2020. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2020-13757
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0142
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 1, 2020

## Description

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).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-rsa Ubuntu 18.04.6 LTS (bionic) | 3.4.2-1ubuntu0.1~esm1 | [python-rsa 3.4.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python-rsa-3.4.2-1ubuntu0.1-esm1.md) | Jun 1, 2020 |
| Linux | python3-rsa Ubuntu 18.04.6 LTS (bionic) | 3.4.2-1ubuntu0.1~esm1 | [python3-rsa 3.4.2-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-python3-rsa-3.4.2-1ubuntu0.1-esm1.md) | Jun 1, 2020 |

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