Stack-based buffer overflow in libcoap - CVE-2025-34468
Published: January 12, 2026
Vulnerability identifier: #VU121175
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2025-34468
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: libcoap.net
Affected software:
libcoap
libcoap
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error within the coap_resolve_address_info() function in src/coap_address.c when proxy logic is enabled. A remote attacker can pass an overly long hostname to the application, trigger a stack-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
How to mitigate CVE-2025-34468
Install updates from vendor's website.