CVE-2026-16443Network attack vectorHinoki check available

Account takeover via disabled SAML signature validation

Published Aug 5, 2026 · Updated Aug 5, 2026

Improper SAML signature verification in Red Hat build of Keycloak allows remote attackers to take over user accounts with forged responses. During SAML identity-provider metadata import, missing key usage attributes cause the broker to disable response signature validation even when metadata supplies a signing certificate. Exploitation requires a configured SAML broker imported from such metadata and knowledge of a target user's external identifier; successful forgery impersonates that user.

CVSS severity7.4
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Improper SAML signature verification in Red Hat build of Keycloak allows remote attackers to take over user accounts with forged responses. During SAML identity-provider metadata import, missing key usage attributes cause the broker to disable response signature validation even when metadata supplies a signing certificate. Exploitation requires a configured SAML broker imported from such metadata and knowledge of a target user's external identifier; successful forgery impersonates that user.

The record

CVE
CVE-2026-16443
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
389 Directory Server
Product
Red Hat build of Keycloak
Classifications
CWE-347, T1606.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record 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 versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat build of KeycloakAffected versions are unavailable in this record.

Published CVSS scores

7.4Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 SAML Tokens

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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