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CVE-2017-5544 Fiberhome CVE debrief

CVE-2017-5544 describes a denial-of-service condition in FiberHome Fengine S5800 switches running V210R240. An attacker who can reach the SSH service can make repeated login attempts, causing SSH login timeouts to increase and connection slots to remain occupied longer. When that happens, legitimate SSH and telnet logins can be refused, and the device may need a restart to recover.

Vendor
Fiberhome
Product
CVE-2017-5544
CVSS
MEDIUM 5.9
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-23
Original CVE updated
2026-05-13
Advisory published
2017-01-23
Advisory updated
2026-05-13

Who should care

Network and infrastructure teams operating FiberHome Fengine S5800 switches, especially instances exposed to untrusted or broad management networks. This matters most for administrators who rely on SSH or telnet for device access and recovery.

Technical summary

NVD classifies the issue as CVSS 3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H with CWE-400 (Uncontrolled Resource Consumption). The vulnerable product scope in the NVD record includes FiberHome Fengine S5800 firmware V210R240. The described failure mode is management-session exhaustion: repeated SSH login activity can lengthen timeouts and consume connection slots, preventing legitimate administrative access over SSH/telnet until the device is restarted.

Defensive priority

Medium. The CVSS score is 5.9, but the impact is operationally significant because the attack is network-reachable, requires no privileges, and can take down management access rather than data confidentiality or integrity.

Recommended defensive actions

  • Restrict switch management access to trusted administrative networks only.
  • Limit or monitor repeated SSH authentication attempts from the management plane.
  • Use out-of-band management paths where possible so a management-plane DoS does not block recovery.
  • Review whether a vendor fix, firmware update, or hardening guidance exists for FiberHome Fengine S5800 V210R240.
  • Prepare a recovery procedure for cases where SSH/telnet becomes unavailable and a restart is required.

Evidence notes

All core claims come from the supplied NVD record and CVE description: the affected product/version is FiberHome Fengine S5800 firmware V210R240; the impact is denial of service against SSH/telnet management access; and the weakness is CWE-400. The supplied references include a SecurityFocus BID 95708 entry and a URL marked "URL Repurposed" for nfcwar.com, so the corpus provides limited third-party context rather than a vendor advisory.

Official resources

Published by CVE on 2017-01-23 07:59:00Z; NVD record modified on 2026-05-13 00:24:29Z. The issue date should be treated as the 2017 publication date, not the later modification date.