Vulnerability · Published Nov 24, 2025 · Assigned by mitre
CVE-2025-65495
High 7.5
In plain English
A high-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 18% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 82.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libcoap3 | no fix listed | DEBIAN-CVE-2025-65495 |
| Debian:13 | libcoap3 | 4.3.4-1.1+deb13u2 | DEBIAN-CVE-2025-65495 |
| Debian:14 | libcoap3 | 4.3.5-2 | DEBIAN-CVE-2025-65495 |
| Ubuntu:22.04:LTS | libcoap2 | no fix listed | UBUNTU-CVE-2025-65495 |
| Ubuntu:22.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65495 |
| Ubuntu:24.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65495 |
| Ubuntu:25.10 | libcoap3 | no fix listed | UBUNTU-CVE-2025-65495 |
| Ubuntu:26.04:LTS | libcoap3 | no fix listed | UBUNTU-CVE-2025-65495 |
| Ubuntu:26.10 | libcoap3 | no fix listed | UBUNTU-CVE-2025-65495 |
Affected products (as reported)
Weakness: CWE-195 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H