CVE-2025-65499: libcoap — Fix

Description

Array index 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 DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1.

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CVSS v3.1 Score

4.3

MEDIUM

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

Weakness Type (CWE)

CWE-129 CWE-129

Affected Products

Vendor	Product	Versions
libcoap	libcoap	All

References

Advisories & Patches

https://github.com/obgm/libcoap/pull/1750

Other References

https://github.com/obgm/libcoap/issues/1747

Frequently Asked Questions

What is CVE-2025-65499? +

Array index 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 DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2025-65499? +

CVE-2025-65499 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-65499? +

CVE-2025-65499 affects products from libcoap, specifically: libcoap. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-65499? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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