CVE-2025-34468

9.8 CRITICAL
Published: December 31, 2025 Modified: January 14, 2026
View on NVD

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).

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/obgm/libcoap/commit/30db3ea
Source: disclosure@vulncheck.com
Patch
https://github.com/obgm/libcoap/pull/1737
Source: disclosure@vulncheck.com
Issue Tracking
https://libcoap.net/
Source: disclosure@vulncheck.com
Product

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
9.8 / 10.0
EPSS (Exploit Probability)
0.3%
55th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

libcoap