How severe is CVE-2026-12804?

CVE-2026-12804 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-12804 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-12804?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-12804 have an EU (EUVD) identifier?

Yes. CVE-2026-12804 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38190.

When was CVE-2026-12804 published?

CVE-2026-12804 was published on 2026-06-21 and last updated on 2026-06-22.

CVE-2026-12804

CVE-2026-12804 is a medium-severity vulnerability with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 5.0
CVSS v4: 2.1
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38190
Weakness: CWE-601
Published: 2026-06-21
Last modified: 2026-06-22

Description

A vulnerability was detected in lemonldap-ng up to 2.23.0. Impacted is an unknown function in the library lemonldap-ng-portal/lib/Lemonldap/NG/Portal/CDC.pm of the component SAML Common Domain Cookie Endpoint. Performing a manipulation of the argument url results in open redirect. The attack is possible to be carried out remotely. The exploit is now public and may be used. Applying a patch is the recommended action to fix this issue. The vendor confirms, that "it has been fixed some days ago and will be available in 2.23.1. CDC is quite never used, so the impact is very low."

Frequently asked questions

What is CVE-2026-12804?: A vulnerability was detected in lemonldap-ng up to 2.23.0. Impacted is an unknown function in the library lemonldap-ng-portal/lib/Lemonldap/NG/Portal/CDC.pm of the component SAML Common Domain Cookie Endpoint. Performing a manipulation of the argument url results in open redirect. The attack is possible to be carried out remotely. The exploit is now public and may be used. Applying a patch is the recommended action to fix this issue. The vendor confirms, that "it has been fixed some days ago and will be available in 2.23.1. CDC is quite never used, so the impact is very low."
How severe is CVE-2026-12804?: CVE-2026-12804 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-12804 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-12804?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-12804 have an EU (EUVD) identifier?: Yes. CVE-2026-12804 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38190.
When was CVE-2026-12804 published?: CVE-2026-12804 was published on 2026-06-21 and last updated on 2026-06-22.

References

Other CWE-601 (Open Redirect) vulnerabilities

CVE-2018-3774 — Critical (CVSS 10.0): Incorrect parsing in url-parse <1.4.3 returns wrong hostname which leads to multiple vulnerabilities such as SSRF, Open…
CVE-2019-25282 — Critical (CVSS 9.8): V-SOL GPON/EPON OLT Platform v2.03 contains an open redirect vulnerability in the script that allows attackers to…
CVE-2020-36912 — Critical (CVSS 9.8): Plexus anblick Digital Signage Management 3.1.13 contains an open redirect vulnerability in the 'PantallaLogin' script…
CVE-2025-43526 — Critical (CVSS 9.8): This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac…
CVE-2025-55031 — Critical (CVSS 9.8): Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An…
CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.

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