Python-RSA decryption of ciphertext leads to DoS
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 software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | rsa | < 4.1 | 4.1 |
References
- https://github.com/sybrenstuvel/python-rsa/issues/146
- https://github.com/sybrenstuvel/python-rsa/issues/146#issuecomment-641845667
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2KILTHBHNSDUCYV22ODLOKTICJJ7JQIQ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZYB65VNILRBTXL6EITQTH2PZPK7I23MW/
- https://usn.ubuntu.com/4478-1/
- https://github.com/advisories/GHSA-537h-rv9q-vvph
- https://nvd.nist.gov/vuln/detail/CVE-2020-13757
- https://github.com/pypa/advisory-database/tree/main/vulns/rsa/PYSEC-2020-99.yaml
- https://github.com/sybrenstuvel/python-rsa
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2KILTHBHNSDUCYV22ODLOKTICJJ7JQIQ
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZYB65VNILRBTXL6EITQTH2PZPK7I23MW
- https://usn.ubuntu.com/4478-1
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-327- Platform
- Python (PyPI)
- Package
rsa- Disclosed
- 01.06.2020
- Updated
- 11.10.2026 11:20
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2020-99 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-537h-rv9q-vvph - CC BY 4.0
Vulnerability history: rsa
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 01.2016 11.2020
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 1
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 2
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 0
earlier: 1
-
Python-RSA decryption of ciphertext leads to DoS this entry
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