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High 8.2Published Dec 31, 2025

CVE-2025-34468libcoap Stack-Based Buffer Overflow in Address Resolution DoS or Potential RCE

Updated under an hour ago ()

Does this affect you?

It affects libcoap. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
8.2 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-121
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
VulnCheck
NVD analysis
Analyzed
Record last updated
Jul 14, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
libcoap libcoap
libcoap:libcoap (from the name)
through 4.3.5; 30db3eaa1f0464722ebea2ca2d5084aebfbd344d not affected
CNA record
libcoap libcoap
libcoap:libcoap
through 4.3.5
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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