Stack-based buffer overflow in libcoap - CVE-2025-34468

Vulnerability details

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.

Affected software

How to mitigate CVE-2025-34468

External References

• https://github.com/obgm/libcoap/commit/30db3ea
• https://github.com/obgm/libcoap/pull/1737
• https://www.vulncheck.com/advisories/libcoap-stack-based-buffer-overflow-in-address-resolution-dos-or-potential-rce

Related Security Bulletins

• Remote code execution in libcoap