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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-34468
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-31 19:15:43 UTC
Updated2026-07-14 23:17:26 UTC
Descriptionlibcoap 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).

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.006370000 probability, percentile 0.464510000 (date 2026-07-16)

Problem Types: CWE-121 | CWE-787 | CWE-121 CWE-121 Stack-based Buffer Overflow

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.2HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.2HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Primary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Libcoap Libcoap All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Libcoap Libcoap affected 4.3.5 semver Not specified
CNA Libcoap Libcoap unaffected 30db3eaa1f0464722ebea2ca2d5084aebfbd344d git Not specified

References

ReferenceSourceLinkTags
github.com/obgm/libcoap/pull/1737 [email protected] github.com Issue Tracking
libcoap.net [email protected] libcoap.net Product
www.vulncheck.com/advisories/libcoap-stack-based-buffer-overflow-in-address-res... [email protected] www.vulncheck.com Third Party Advisory
github.com/obgm/libcoap/commit/30db3ea [email protected] github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: SecMate (en)

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