CVE-2026-49284: SimpleSAMLphp versions before 1.18.6 contain an information disclosure vulnerability

Routine

HIGH 7.1UPGRADE

CVE-2026-49284 is a high-severity flaw (CVSS 7.1) affecting simplesamlphp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-345
Published	2026-07-17
Last modified	2026-07-30

Publisher (CNA): GitHub, Inc. · Vendor: simplesamlphp

Last updated 2026-07-30 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 20:17 UTCPublished CVE record published
2026-07-30 13:39 UTCUpdated Record last modified

simplesamlphp simplesamlphp UPGRADE

Affected: < 2.4.7 · >= 2.5.0 and < 2.5.2

Fixed in: 2.4.7, 2.5.2

Safe to downgrade to: a release before 2.5.0

1. Check installed version

apt-cache policy simplesamlphp || rpm -q simplesamlphp || simplesamlphp --version

2. UPGRADE to 2.4.7 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade simplesamlphp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade simplesamlphp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.5.0 (Debian / Ubuntu)

apt-cache madison simplesamlphp sudo apt install simplesamlphp=<VERSION_BEFORE_2.5.0> sudo apt-mark hold simplesamlphp

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list simplesamlphp sudo dnf downgrade simplesamlphp-<VERSION_BEFORE_2.5.0> sudo dnf versionlock add simplesamlphp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-49284?

simplesamlphp: upgrade to 2.4.7, 2.5.2. Exact commands for each OS are on this page.

Is CVE-2026-49284 being exploited?

CVE-2026-49284 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-49284 affect?

CVE-2026-49284 affects simplesamlphp. Severity is high (CVSS 7.1). 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

How urgent is CVE-2026-49284?

Priority 28/100. High severity

References

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