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Fencer Intel
high 7.5

CVE-2020-3574 json

Cisco IP Phone TCP Packet Flood Denial of Service Vulnerability

published 6y ago modified 4mo ago also EUVD-2020-24845

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
8.0%
EPSS 8.0% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

A vulnerability in the TCP packet processing functionality of Cisco IP Phones could allow an unauthenticated, remote attacker to cause the phone to stop responding to incoming calls, drop connected calls, or unexpectedly reload. The vulnerability is due to insufficient TCP ingress packet rate limiting. An attacker could exploit this vulnerability by sending a high and sustained rate of crafted TCP traffic to the targeted device. A successful exploit could allow the attacker to impact operations of the phone or cause the phone to reload, leading to a denial of service (DoS) condition.

Patch / fix

  • cisco ip_dect_210_firmware 4.8.1
  • cisco ip_dect_6825_firmware 4.8.1
  • cisco ip_phone_8811_firmware 11.3.2
  • cisco ip_phone_8841_firmware 11.3.2
  • cisco ip_phone_8851_firmware 11.3.2
  • cisco ip_phone_8861_firmware 11.3.2
  • cisco webex_room_phone_firmware 1.2.0

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

8.03% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • Cisco Cisco IP Phones with Multiplatform Firmware

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.