Vulnerability in python-pysaml2 (DEBIAN-CVE-2021-21238)

Summary

Vulnerability in python-pysaml2 (DEBIAN-CVE-2021-21238). Data can be tampered with by attackers. Mitigation: upgrade to 6.5.1-1 or later.

Original description

The description as published by the source.

PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability. All users of pysaml2 that need to validate signed SAML documents are impacted. The vulnerability is a variant of XML Signature wrapping because it did not validate the SAML document against an XML schema. This allowed invalid XML documents to be processed and such a document can trick pysaml2 with a wrapped signature. This is fixed in PySAML2 6.5.0.

Source: OSV.dev (Open Source Vulnerabilities) OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as DEBIAN-CVE-2021-21238 has been found in python-pysaml2.
Data can be tampered with by attackers.
What to do: upgrade python-pysaml2 to 6.5.1-1 or later.
If unsure, ask your IT team or search "python-pysaml2 DEBIAN-CVE-2021-21238" on the vendor's site.

DEBIAN-CVE-2021-21238 (python-pysaml2)
Attack vector: remote (network-reachable) / unauthenticated
Patched: 6.5.1-1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in python-pysaml2.

📍 Affected scope

Check the vendor advisory for the affected versions of python-pysaml2.

🔥 Severity

Severity: ?. Data can be tampered with by attackers.

🔧 How to fix

Update to 6.5.1-1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'python-pysaml2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'python-pysaml2' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で python-pysaml2 を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade python-pysaml2 to 6.5.1-1
```
ステージング環境で 6.5.1-1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Debian:12 python-pysaml2

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.1-1"}]}]

Debian:13 python-pysaml2

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.1-1"}]}]

Debian:14 python-pysaml2

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.1-1"}]}]

References

advisory security-tracker.debian.org