Vulnerability · Published Nov 24, 2025 · Assigned by mitre
CVE-2025-65499
Medium 4.3
In plain English
A medium-severity security flaw in the libcoap3 package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 79.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libcoap3 | no fix listed | DEBIAN-CVE-2025-65499 |
| Debian:13 | libcoap3 | 4.3.4-1.1+deb13u2 | DEBIAN-CVE-2025-65499 |
| Debian:14 | libcoap3 | 4.3.5-2 | DEBIAN-CVE-2025-65499 |
| Ubuntu:22.04:LTS | libcoap2 | no fix listed | UBUNTU-CVE-2025-65499 |
| Ubuntu:22.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65499 |
| Ubuntu:24.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65499 |
| Ubuntu:25.10 | libcoap3 | no fix listed | UBUNTU-CVE-2025-65499 |
| Ubuntu:26.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65499 |
| Ubuntu:26.10 | libcoap3 | no fix listed | UBUNTU-CVE-2025-65499 |
Affected products (as reported)
Weakness: CWE-129 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L