How severe is CVE-2025-41066?

CVE-2025-41066 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2025-41066 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-41066?

CVE-2025-41066 affects Horde Groupware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-41066?

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

Does CVE-2025-41066 have an EU (EUVD) identifier?

Yes. CVE-2025-41066 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-200240.

When was CVE-2025-41066 published?

CVE-2025-41066 was published on 2025-12-02 and last updated on 2026-06-17.

CVE-2025-41066

CVE-2025-41066 is a medium-severity vulnerability in Horde Groupware with a CVSS 3.x base score of 5.3. 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 6.9
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-200240
Weakness: CWE-200
Affected product: Horde Groupware
Published: 2025-12-02
Last modified: 2026-06-17

Description

Horde Groupware v5.2.22 has a user enumeration vulnerability that allows an unauthenticated attacker to determine the existence of valid accounts on the system. To exploit the vulnerability, an HTTP request must be sent to ‘/imp/attachment.php’ including the parameters ‘id’ and ‘u’. If the specified user exists, the server will return the download of an empty file; if it does not exist, no download will be initiated, which unequivocally reveals the validity of the user.

Frequently asked questions

What is CVE-2025-41066?: Horde Groupware v5.2.22 has a user enumeration vulnerability that allows an unauthenticated attacker to determine the existence of valid accounts on the system. To exploit the vulnerability, an HTTP request must be sent to ‘/imp/attachment.php’ including the parameters ‘id’ and ‘u’. If the specified user exists, the server will return the download of an empty file; if it does not exist, no download will be initiated, which unequivocally reveals the validity of the user.
How severe is CVE-2025-41066?: CVE-2025-41066 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2025-41066 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-41066?: CVE-2025-41066 affects Horde Groupware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-41066?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-41066 have an EU (EUVD) identifier?: Yes. CVE-2025-41066 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-200240.
When was CVE-2025-41066 published?: CVE-2025-41066 was published on 2025-12-02 and last updated on 2026-06-17.

References

https://www.incibe.es/en/incibe-cert/notices/aviso/disclosure-sensitive-information-horde-groupware

Affected products (1)

cpe:2.3:a:horde:groupware:5.2.22:*:*:*:-:*:*:*

More vulnerabilities in Horde Groupware

CVE-2008-7219 — Critical (CVSS 10.0): Horde Kronolith H3 2.1 before 2.1.7 and 2.2 before 2.2-RC2; Nag H3 2.1 before 2.1.4 and 2.2 before 2.2-RC2; Mnemo H3…
CVE-2008-7218 — Critical (CVSS 10.0): Unspecified vulnerability in the Horde API in Horde 3.1 before 3.1.6 and 3.2 before 3.2 before 3.2-RC2; Turba H3 2.1…
CVE-2020-8518 — Critical (CVSS 9.8): Horde Groupware Webmail Edition 5.2.22 allows injection of arbitrary PHP code via CSV data, leading to remote code…
CVE-2013-6364 — High (CVSS 8.8): Horde Groupware Webmail Edition has CSRF and XSS when saving search as a virtual address book
CVE-2019-12095 — High (CVSS 8.8): Horde Trean, as used in Horde Groupware Webmail Edition through 5.2.22 and other products, allows CSRF, as demonstrated…
CVE-2019-9858 — High (CVSS 8.8): Remote code execution was discovered in Horde Groupware Webmail 5.2.22 and 5.2.17. Horde/Form/Type.php contains a…

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