What is the CVSS score of CVE-2021-21239?

CVE-2021-21239 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N. EPSS exploitation probability: 1.2%.

Is there a public PoC exploit available for CVE-2021-21239?

Yes, a public proof-of-concept exploit is available for CVE-2021-21239. Prioritise patching immediately. EPSS: 1.2%.

Is there a patch available for CVE-2021-21239?

Yes, a patch is available for CVE-2021-21239. Update the affected software to the latest version immediately.

Python CVE-2021-21239

MEDIUM

Improper Verification of Cryptographic Signature (CWE-347)

2021-01-21 security-advisories@github.com

Python Information Disclosure Jwt Attack Pysaml2 Debian Linux

6.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.5 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Lifecycle Timeline

CVE Published

Jan 21, 2021 - 15:15 nvd

MEDIUM 6.5

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

1 pypi packages depend on pysaml2 (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 6.5.0.

DescriptionNVD

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 ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only _x509 certificates_ for the verification process of the SAML document signature. This is fixed in PySAML2 6.5.0.

AnalysisAI

PySAML2 is a pure python implementation of SAML Version 2 Standard. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified under CWE-347. 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 ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only _x509 certificates_ for the verification process of the SAML document signature. This is fixed in PySAML2 6.5.0. Affected products include: Pysaml2 Project Pysaml2, Debian Debian Linux. Version information: Version 2.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.