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Fencer Vulns
high 7.5

CVE-2020-5390 json

Improper Verification of Cryptographic Signature in PySAML2

published 2020-01-13 6 y ago modified 2026-06-17 4 mo ago also GHSA-qf7v-8hj3-4xw7 , PYSEC-2020-94 , EUVD-2020-0157

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi pysaml2 5.0.0
  • pysaml2_project pysaml2 5.0.0
  • python-pysaml2 Debian 14, Debian 13, Debian 12 4.5.0-7

debian advisories DEBIAN-CVE-2020-5390

  • python-pysaml2 Ubuntu 16.04 LTS 3.0.0-3ubuntu1.16.04.4
  • python-pysaml2 Ubuntu 18.04 LTS 4.0.2-0ubuntu3.1

ubuntu advisories UBUNTU-CVE-2020-5390

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • spark OpenStack Cloud Crowbar 9, OpenStack Cloud 9 2.2.3-5.3.3
  • grafana OpenStack Cloud Crowbar 9, OpenStack Cloud 9 6.7.4-3.20.1
  • influxdb OpenStack Cloud Crowbar 9, OpenStack Cloud 9 1.3.8-4.3.3
  • ardana-mq OpenStack Cloud 9 9.0+git.1605174486.a78ddce-3.19.2
  • crowbar-core OpenStack Cloud Crowbar 9 6.0+git.1606314264.bf9ada813-3.31.2
  • python-Jinja2 OpenStack Cloud Crowbar 9, OpenStack Cloud 9 2.10.1-3.3.3
  • python-pytest OpenStack Cloud Crowbar 9, OpenStack Cloud 9 3.7.4-3.3.3
  • ardana-tempest OpenStack Cloud 9 9.0+git.1603378983.fc0bca9-3.19.2

suse advisories SUSE-SU-2020:3897-1SUSE-RU-2020:2072-1SUSE-SU-2020:1901-1

  • python-pysaml2 openSUSE Tumbleweed 7.5.4-1.1
  • python-pysaml2 openSUSE Tumbleweed 7.4.2-1.2

opensuse advisories openSUSE-SU-2026:11524-1openSUSE-SU-2024:14156-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-5390 updated cvss 7.5

python-pysaml2: does not check that the signature in a SAML document is enveloped

  • Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) python-pysaml2 Red Hat OpenStack Platform 10 (Newton) python-pysaml2 Red Hat OpenStack Platform 13 (Queens) python-pysaml2 Red Hat OpenStack Platform 15 (Stein) python3-pysaml2 Red Hat OpenStack Platform 16 (Train) python-pysaml2, python3-pysaml2
    affected: workaround, no fix planned “There is no known mitigation for this issue, the flaw can only be resolved by applying updates.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi pysaml2
<5.0.0
5.0.0

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.