CVE-2025-34468

Description

libcoap versions up to and including 4.3.5, prior to commit 30db3ea, contain a stack-based buffer overflow in address resolution when attacker-controlled hostname data is copied into a fixed 256-byte stack buffer without proper bounds checking. A remote attacker can trigger a crash and potentially achieve remote code execution depending on compiler options and runtime memory protections. Exploitation requires the proxy logic to be enabled (i.e., the proxy request handling code path in an application using libcoap).

CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-121 CWE-121

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
libcoap	libcoap	< 4.3.5

References

Advisories & Patches

https://github.com/obgm/libcoap/commit/30db3ea

Other References

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

Frequently Asked Questions

What is CVE-2025-34468? +

libcoap versions up to and including 4.3.5, prior to commit 30db3ea, contain a stack-based buffer overflow in address resolution when attacker-controlled hostname data is copied into a fixed 256-byte stack buffer without proper bounds checking. A remote attacker can trigger a crash and potentially achieve remote code execution depending on compiler options and runtime memory protections. Exploitation requires the proxy logic to be enabled (i.e., the proxy request handling code path in an application using libcoap). It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2025-34468? +

CVE-2025-34468 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-34468? +

CVE-2025-34468 affects products from libcoap, specifically: libcoap. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-34468? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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