How severe is CVE-2017-15887?

CVE-2017-15887 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-15887 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-15887?

CVE-2017-15887 affects Synology Carddav Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-15887?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-15887 published?

CVE-2017-15887 was published on 2017-11-07 and last updated on 2026-06-17.

CVE-2017-15887

CVE-2017-15887 is a critical-severity vulnerability in Synology Carddav Server with a CVSS 3.x base score of 9.8. 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-307.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-307
Affected product: Synology Carddav Server
Published: 2017-11-07
Last modified: 2026-06-17

Description

An improper restriction of excessive authentication attempts vulnerability in /principals in Synology CardDAV Server before 6.0.7-0085 allows remote attackers to obtain user credentials via a brute-force attack.

Frequently asked questions

What is CVE-2017-15887?: An improper restriction of excessive authentication attempts vulnerability in /principals in Synology CardDAV Server before 6.0.7-0085 allows remote attackers to obtain user credentials via a brute-force attack.
How severe is CVE-2017-15887?: CVE-2017-15887 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-15887 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-15887?: CVE-2017-15887 affects Synology Carddav Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-15887?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-15887 published?: CVE-2017-15887 was published on 2017-11-07 and last updated on 2026-06-17.

References

https://www.synology.com/en-global/support/security/Synology_SA_17_64_CardDAV_Server

Affected products (1)

cpe:2.3:a:synology:carddav_server:*:*:*:*:*:*:*:*

More vulnerabilities in Synology Carddav Server

CVE-2022-27613 — High (CVSS 8.3): Improper neutralization of special elements used in an SQL command ('SQL Injection') vulnerability in webapi component…
CVE-2018-8928 — Medium (CVSS 6.5): Cross-site scripting (XSS) vulnerability in Address Book Editor in Synology CardDAV Server before 6.0.8-0086 allows…

All CVEs affecting Synology Carddav Server →

Other CWE-307 (Improper Restriction of Excessive Authentication Attempts) vulnerabilities

CVE-2026-6853 — Critical (CVSS 9.8): Improper restriction of excessive authentication attempts vulnerability in Başbelen Group Food Cafe Businesses…
CVE-2026-8760 — Critical (CVSS 9.8): The Login with OTP plugin for WordPress is vulnerable to authentication bypass in all versions up to, and including,…
CVE-2020-37228 — Critical (CVSS 9.8): iDS6 DSSPro Digital Signage System 6.2 contains a CAPTCHA security bypass vulnerability that allows attackers to bypass…
CVE-2026-33879 — Critical (CVSS 9.8): Federated Learning and Interoperability Platform (FLIP) is an open-source platform for federated training and…
CVE-2026-33640 — Critical (CVSS 9.8): Outline is a service that allows for collaborative documentation. Outline implements an Email OTP login flow for users…
CVE-2026-31851 — Critical (CVSS 9.8): Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 does not implement rate limiting or account lockout…

Browse all CWE-307 (Improper Restriction of Excessive Authentication Attempts) vulnerabilities →