CVE-2025-65493Network attack vector

Service crash via unchecked OpenSSL BIO data

Published Nov 24, 2025 · Updated Nov 24, 2025

NULL pointer dereference in OISM libcoap 4.3.5 allows remote attackers to crash a service through a crafted DTLS/TLS connection. In coap_dgram_write() and coap_dgram_ctrl(), src/coap_openssl.c dereferences data returned by BIO_get_data() without first rejecting NULL. An unauthenticated connection can interrupt only a service built with the OpenSSL DTLS/TLS backend; no data disclosure or modification is reported.

CVSS severity7.5
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in OISM libcoap 4.3.5 allows remote attackers to crash a service through a crafted DTLS/TLS connection. In coap_dgram_write() and coap_dgram_ctrl(), src/coap_openssl.c dereferences data returned by BIO_get_data() without first rejecting NULL. An unauthenticated connection can interrupt only a service built with the OpenSSL DTLS/TLS backend; no data disclosure or modification is reported.

The record

CVE
CVE-2025-65493
Published
Nov 24, 2025
Updated
Nov 24, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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