CVE-2021-33054Network attack vector

User impersonation via ignored SAML signatures

Published Jun 4, 2021 · Updated Aug 3, 2024

SAML signature bypass in SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 allows remote attackers to impersonate users. The processAuthnResponse method in SOGoSAML2Session sets Lasso's signature-verification hint to ignore before processing an authentication response, causing unsigned or forged assertions to be accepted. The flaw is reachable only when SAML authenticates users, and its documented consequence is account impersonation.

CVSS severity7.5
High
EPSS probability1.00%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SAML signature bypass in SOGo 2.x before 2.4.1 and 3.x through 5.x before 5.1.1 allows remote attackers to impersonate users. The processAuthnResponse method in SOGoSAML2Session sets Lasso's signature-verification hint to ignore before processing an authentication response, causing unsigned or forged assertions to be accepted. The flaw is reachable only when SAML authenticates users, and its documented consequence is account impersonation.

The record

CVE
CVE-2021-33054
Published
Jun 4, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347, T1606.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 4, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1606.002Forge Web Credentials: SAML Tokens

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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