How severe is CVE-2025-6999?

CVE-2025-6999 has a CVSS 4.0 base score of 6.9, rated medium severity.

Is CVE-2025-6999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-6999?

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

Does CVE-2025-6999 have an EU (EUVD) identifier?

Yes. CVE-2025-6999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29270.

When was CVE-2025-6999 published?

CVE-2025-6999 was published on 2025-09-15 and last updated on 2026-06-17.

CVE-2025-6999

CVE-2025-6999 is a medium-severity vulnerability with a CVSS 4.0 base score of 6.9. 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-444.

Key facts

Severity: Medium (CVSS 4.0 base score 6.9)
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-29270
Weakness: CWE-444
Published: 2025-09-15
Last modified: 2026-06-17

Description

An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.This issue affects Fireware OS: from 12.0 through 12.11.2.

Frequently asked questions

What is CVE-2025-6999?: An HTTP Request Smuggling [CWE-444] vulnerability in the Authentication portal of WatchGuard Fireware OS allows a remote attacker to evade request parameter sanitation and perform a reflected self-Cross-Site Scripting (XSS) attack.This issue affects Fireware OS: from 12.0 through 12.11.2.
How severe is CVE-2025-6999?: CVE-2025-6999 has a CVSS 4.0 base score of 6.9, rated medium severity.
Is CVE-2025-6999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-6999?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-6999 have an EU (EUVD) identifier?: Yes. CVE-2025-6999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29270.
When was CVE-2025-6999 published?: CVE-2025-6999 was published on 2025-09-15 and last updated on 2026-06-17.

References

https://www.watchguard.com/wgrd-psirt/advisory/wgsa-2025-00014

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