HIGH
CVE-2025-65495
CWE-195Published: November 24, 2025· Updated: Jun 17, 2026
7.5
CVSS v3.1
Official Description
Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.
Technical Analysis
CVE-2025-65495 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
libcoap1 product(s)
libcoap
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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GitHub PoC Search
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Rapid7 / Metasploit
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Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
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Official Patches & Advisories
All References (2)
→
https://github.com/obgm/libcoap/issues/1744Issue Tracking
→
https://github.com/obgm/libcoap/pull/1750Issue Tracking · Patch
Quick Facts
CVE IDCVE-2025-65495
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-195
CISA KEVNo
Affected1 vendor(s)
PublishedNov 24, 2025
Related CVEs (CWE-195)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2025-65495 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.