# CVE-2025-65501: libcoap3: Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote attackers to cause a denial...

CVE-2025-65501 is fixed in libcoap3 on 1 platform, first by DEBIAN-CVE-2025-65501, released November 24, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-65501
- Priority: Routine
- CVSS: 4.3 (medium)
- EPSS: 0.0028
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 24, 2025

## Description

Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a DTLS handshake where SSL_get_app_data() returns NULL.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libcoap3 Debian 13.5 (trixie) | 4.3.4-1.1+deb13u2 | [DEBIAN-CVE-2025-65501](https://patchblox.com/security/data/fix/linux/debian-cve-2025-65501.md) | Nov 24, 2025 |
| Linux | libcoap3 Debian 14 | 4.3.5-2 | [DEBIAN-CVE-2025-65501](https://patchblox.com/security/data/fix/linux/debian-cve-2025-65501.md) | Nov 24, 2025 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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