CVE-2025-31335Network attack vector

Signed SAML message forgery via parameter replay

Published Mar 28, 2025 · Updated Mar 28, 2025

Signature verification bypass in Shibboleth Consortium OpenSAML C++ before 3.3.1 allows remote attackers to forge signed SAML messages. Non-XML signature verification accepts manipulated parameters combined with content replayed from earlier requests as a valid signed message. Exploitation requires a non-XML signature binding; the SP enables HTTP-POST-SimpleSign by default, and successful forgery can bypass SSO authentication.

CVSS severity4.0
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Signature verification bypass in Shibboleth Consortium OpenSAML C++ before 3.3.1 allows remote attackers to forge signed SAML messages. Non-XML signature verification accepts manipulated parameters combined with content replayed from earlier requests as a valid signed message. Exploitation requires a non-XML signature binding; the SP enables HTTP-POST-SimpleSign by default, and successful forgery can bypass SSO authentication.

The record

CVE
CVE-2025-31335
Published
Mar 28, 2025
Updated
Mar 28, 2025
Vendor
Shibboleth Consortium
Product
OpenSAML C++
Classifications
CWE-347, T1606.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shibboleth Consortium · OpenSAML C++version=0 <3.3.1

Published CVSS scores

4.0UbuntuCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
4.0SUSECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
4.0MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/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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