Vulnerability · Published Aug 4, 2026 · Assigned by mitre
CVE-2026-67858
High 7.5
In plain English
A high-severity buffer overflow in the open62541 package (Debian). Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 59% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.9%top 41.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Buffer Overflow vulnerability exists in open62541 1.5.5 when the Local Discovery Server (LDS) is built with multicast discovery enabled through the MDNSD backend. An unauthenticated remote attacker can send a RegisterServer or RegisterServer2 request containing many unique discoveryUrls. This allows remote attackers to cause a denial of service.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | open62541 | no fix listed | DEBIAN-CVE-2026-67858 |
| Debian:14 | open62541 | no fix listed | DEBIAN-CVE-2026-67858 |
| Ubuntu:26.04:LTS | open62541 | no fix listed | UBUNTU-CVE-2026-67858 |
| Ubuntu:26.10 | open62541 | no fix listed | UBUNTU-CVE-2026-67858 |
Affected products (as reported)
Weakness: CWE-120 · Vector: CVSS:3.1/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N
References
- https://github.com/open62541/open62541/issues/8094
- https://github.com/open62541/open62541/tree/master/examples/discovery
- https://github.com/open62541/open62541/blob/master/src/server/ua_services_discovery.c
- https://github.com/open62541/open62541/blob/master/src/server/ua_discovery_mdns.c
- https://github.com/open62541/open62541/blob/master/doc/building.rst