CVE-2020-5390: PySAML2 before 5.0.0 does not check that the signature in a SAML document is enveloped and thus signature wrap

Q: How do I fix CVE-2020-5390?

pysaml2: upgrade to 5.0.0; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2020-5390 being exploited?

CVE-2020-5390 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-5390 affect?

CVE-2020-5390 affects pysaml2, ubuntu linux, debian linux. Severity is high (CVSS 7.5). 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 sig

Q: How urgent is CVE-2020-5390?

Priority 53/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

This month

HIGH 7.5REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2020-5390 is a high-severity flaw (CVSS 7.5) affecting pysaml2, ubuntu linux, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-347
Published	2020-01-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · pysaml2 project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-01-13 19:15 UTCPublished CVE record published
2026-06-17 03:21 UTCUpdated Record last modified

pysaml2 project pysaml2 UPGRADE

Affected: < 5.0.0

Fixed in: 5.0.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy pysaml2 || rpm -q pysaml2 || pysaml2 --version

2. UPGRADE to 5.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pysaml2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pysaml2

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

canonical ubuntu linux MITIGATE

Affected: 16.04 · 18.04 · 19.04 · 19.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-5390?

pysaml2: upgrade to 5.0.0; ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-5390 being exploited?

CVE-2020-5390 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-5390 affect?

CVE-2020-5390 affects pysaml2, ubuntu linux, debian linux. Severity is high (CVSS 7.5). 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 sig

How urgent is CVE-2020-5390?

Priority 53/100. High severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2017-1000433 HIGH 8.1 UPGRADE MITIGATE pysaml2 version 4.4.0 and older accept any password when run with python optimizations enabled
CVE-2017-1000246 MEDIUM 5.3 UPGRADE Python package pysaml2 version 4.4.0 and earlier reuses the initialization vector across encryptions in the ID
CVE-2016-10149 HIGH 7.5 UPGRADE MITIGATE XML External Entity (XXE) vulnerability in PySAML2 4.4.0 and earlier allows remote attackers to read arbitrary
CVE-2016-10127 CRITICAL 9.0 MITIGATE PySAML2 allows remote attackers to conduct XML external entity (XXE) attacks via a crafted SAML XML request or

References

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