SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-1378

A vulnerability in the SSH service of the Cisco StarOS operating system could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition.

HIGH 7.5EPSS 1.50%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.50%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

A vulnerability in the SSH service of the Cisco StarOS operating system could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to a logic error that may occur under specific traffic conditions. An attacker could exploit this vulnerability by sending a series of crafted packets to an affected device. A successful exploit could allow the attacker to prevent the targeted service from receiving any traffic, which would lead to a DoS condition on the affected device.

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
1.50% probability · 74th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-400
Affected
cisco/staros
Source
psirt@cisco.com
EPSS trend
0%3%5%26 October 2026: 1.50%26 October 202626 October 2026

EPSS 1.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.