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CVE-2021-21239 · cross-distro fix matrix

CVE-2021-21239: PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability. Users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. PySAML2 does not e

Affects 8 Linux releases across 8 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2021-21239 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

  • python-pysaml2→ fixed in6.5.1-1urgency: not yet assigned
    sudo apt-get install --only-upgrade -y python-pysaml2

Debian bookworm

Source: Debian Security Tracker

  • python-pysaml2→ fixed in6.5.1-1urgency: not yet assigned
    sudo apt-get install --only-upgrade -y python-pysaml2

Debian trixie

Source: Debian Security Tracker

  • python-pysaml2→ fixed in6.5.1-1urgency: not yet assigned
    sudo apt-get install --only-upgrade -y python-pysaml2

Alpine v3.20

Source: Alpine secdb

  • py3-saml2→ fixed in6.5.0-r0
    apk update && apk add --upgrade py3-saml2

Alpine v3.21

Source: Alpine secdb

  • py3-saml2→ fixed in6.5.0-r0
    apk update && apk add --upgrade py3-saml2

Alpine edge

Source: Alpine secdb

  • py3-saml2→ fixed in6.5.0-r0
    apk update && apk add --upgrade py3-saml2

Alpine v3.18

Source: Alpine secdb

  • py3-saml2→ fixed in6.5.0-r0
    apk update && apk add --upgrade py3-saml2

Alpine v3.19

Source: Alpine secdb

  • py3-saml2→ fixed in6.5.0-r0
    apk update && apk add --upgrade py3-saml2
Are YOU affected by CVE-2021-21239?

5-second check on your actual server. Reads /etc/os-release, uname -r, and the distro's package manager; matches against this same cross-source index live.

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