SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2025-6599

An uncontrolled resource consumption vulnerability in the web server of Zyxel DX3301-T0 firmware version 5.50(ABVY.6.3)C0 and earlier could allow an attacker to perform Slowloris‑style denial‑of‑service (DoS) attacks.

HIGH 7.5EPSS 0.31%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

An uncontrolled resource consumption vulnerability in the web server of Zyxel DX3301-T0 firmware version 5.50(ABVY.6.3)C0 and earlier could allow an attacker to perform Slowloris‑style denial‑of‑service (DoS) attacks. Such attacks may temporarily block legitimate HTTP requests and partially disrupt access to the web management interface, while other networking services remain unaffected.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
0.31% probability · 24th percentile
CISA KEV
Not listed
Weakness
CWE-400
Affected
zyxel/lte3301-plus firmware · zyxel/nr5103 firmware · zyxel/nr5103e firmware · zyxel/nr5309 firmware · zyxel/nr7302 firmware · zyxel/nr7303 firmware · zyxel/nebula fwa505 firmware · zyxel/nebula fwa510 firmware · zyxel/nebula fwa515 firmware · zyxel/nebula fwa710 firmware · zyxel/dm4200-b0 firmware · zyxel/dx3300-t0 firmware · zyxel/dx3300-t1 firmware · zyxel/dx3301-t0 firmware · zyxel/dx4510-b1 firmware · zyxel/dx5401-b0 firmware · zyxel/dx5401-b1 firmware · zyxel/ee3301-00 firmware · zyxel/ee5301-00 firmware · zyxel/ee6510-10 firmware · +40 more
Source
security@zyxel.com.tw

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.