CVE-2023-31447

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-08-21 · updated 2026-06-17
Weakness: CWE-94

Description

user_login.cgi on Draytek Vigor2620 devices before 3.9.8.4 (and on all versions of Vigor2925 devices) allows attackers to send a crafted payload to modify the content of the code segment, insert shellcode, and execute arbitrary code.

Affected products

DrayTek Vigor2620 Firmware: before 3.9.8.4 — fixed in 3.9.8.4
DrayTek Vigor2625 Firmware: all versions

How to fix

Upgrade to a fixed version: DrayTek Vigor2620 Firmware 3.9.8.4. Check the vendor advisory for mitigations.

References

https://draytek.com
https://gist.github.com/rrrrrrri/013c9eef64b265af4163478bfcf29ff4
https://draytek.com
https://gist.github.com/rrrrrrri/013c9eef64b265af4163478bfcf29ff4

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