// For flags

CVE-2021-28091

lasso: XML signature wrapping vulnerability when parsing SAML responses

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Lasso all versions prior to 2.7.0 has improper verification of a cryptographic signature.

Lasso todas las versiones anteriores a versión 2.7.0, presentan una verificación inapropiada de una firma criptográfica

An XML Signature Wrapping (XSW) vulnerability was found in Lasso. This flaw allows an attacker to modify a valid SAML response to include an unsigned SAML assertion, which may be used to impersonate another valid user recognized by the service using Lasso. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability.

The lasso packages provide the Lasso library that implements the Liberty Alliance Single Sign-On standards, including the SAML and SAML2 specifications. It allows handling of the whole life-cycle of SAML-based federations and provides bindings for multiple languages.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-03-08 CVE Reserved
  • 2021-06-02 CVE Published
  • 2024-08-03 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-345: Insufficient Verification of Data Authenticity
  • CWE-347: Improper Verification of Cryptographic Signature
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Entrouvert
Search vendor "Entrouvert"
 Lasso
Search vendor "Entrouvert" for product "Lasso"
 < 2.7.0
Search vendor "Entrouvert" for product "Lasso" and version " < 2.7.0"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 10.0
Search vendor "Debian" for product "Debian Linux" and version "10.0"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected