CVE-2020-5390
HIGHDescription
PySAML2 before 5.0.0 does not check that the signature in a SAML document is enveloped and thus signature wrapping is effective, i.e., it is affected by XML Signature Wrapping (XSW). The signature information and the node/object that is signed can be in different places and thus the signature verification will succeed, but the wrong data will be used. This specifically affects the verification of assertion that have been signed.
How to fix
This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.
This Ubuntu release reached end-of-life on 2023-05-31. Extended security maintenance is available until 2028-04-01.
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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Exploit Intelligence
Moderate risk: more likely to be exploited than 67% of all known CVEs.
References
Related Vulnerabilities
Other CWE-347 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2018-16042 | Medium | 6.5 | 82% | - | - |
| CVE-2025-59718 | Critical | 9.8 | 68% | KEV | Fix |
| CVE-2025-25292 | Critical | 9.8 | 65% | - | Fix |
| CVE-2026-48558 | Critical | 10.0 | 64% | KEV | Fix |
| CVE-2021-22160 | Critical | 9.8 | 53% | - | Fix |
| CVE-2013-3900 | Medium | 5.5 | 45% | KEV | - |
Common questions
How do I fix CVE-2020-5390?
Published advisories record a fix for 3 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2020-5390 being actively exploited?
Not that we know of. CVE-2020-5390 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 67% of all scored CVEs.
How severe is CVE-2020-5390?
CVE-2020-5390 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2020-5390 affect?
Published advisories record a fix for python-pysaml2 (Debian), python-pysaml2 (Ubuntu), python3-pysaml2 (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-17.