SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2025-27458

Since all VNC communication is unencrypted, an attacker can obtain the challenge and response and try to derive the password from this information.

HIGH 7.5EPSS 0.19%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The VNC authentication mechanism bases on a challenge-response system where both server and client use the same password for encryption. The challenge is sent from the server to the client, is encrypted by the client and sent back. The server does the same encryption locally and if the responses match it is prooven that the client knows the correct password. Since all VNC communication is unencrypted, an attacker can obtain the challenge and response and try to derive the password from this information.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
0.19% probability · 8th percentile
CISA KEV
Not listed
Weakness
CWE-327
Affected
endress/meac300-fnade4 firmware
Source
psirt@sick.de

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