CyberSecBulletin
CVE-2026-49284NVD status: Analyzed

simplesamlphp: Insufficient Verification of Data Authenticity

Published Updated By the CyberSecBulletin desk

CVE-2026-49284 is a high-severity insufficient verification of data authenticity vulnerability in simplesamlphp, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected simplesamlphp versions: < 2.4.7; >= 2.5.0-rc1, < 2.5.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.22% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of simplesamlphp you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Simplesamlphpsimplesamlphp< 2.4.7; >= 2.5.0-rc1, < 2.5.2Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
LowSome restricted data can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N. Scored by CNA (github.com).

Official description

SimpleSAMLphp versions before 1.18.6 contain an information disclosure vulnerability. Prior to 2.4.7 and 2.5.2, SimpleSAMLphp's SAML SP ACS path does not enforce the IdP selected for an SP-initiated login when unsigned Response/InResponseTo is combined with a signed assertion lacking SubjectConfirmationData/InResponseTo, allowing a response issued by one trusted IdP to be bound to SP state created for another IdP and bypass flows that route users to a specific IdP, including deployments that set enable_unsolicited to false. This issue is fixed in versions 2.4.7 and 2.5.2.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Insufficient Verification of Data Authenticity

The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

More Insufficient Verification of Data Authenticity vulnerabilities (CWE-345)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Insufficient Verification of Data Authenticity vulnerabilities

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