Vulnerability · Published Sep 5, 2026 · Assigned by Tcpdump
CVE-2026-18238OOBR in rpcap client in libpcap before 1.10.7
Medium 5.0
In plain English
A medium-severity security flaw in libpcap from The Tcpdump Group. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The rpcap client code that processes a RPCAP_MSG_PACKET message received from the server incorrectly validates its headers. A malicious server can send a crafted message and cause the client to treat up to 20 bytes of the client process memory beyond the end of the buffer as if it was a part of the captured packet.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libpcap | no fix listed | DEBIAN-CVE-2026-18238 |
| Debian:13 | libpcap | no fix listed | DEBIAN-CVE-2026-18238 |
| Debian:14 | libpcap | 1.10.7-1 | DEBIAN-CVE-2026-18238 |
| Ubuntu:22.04:LTS | libpcap | no fix listed | UBUNTU-CVE-2026-18238 |
| Ubuntu:24.04:LTS | libpcap | no fix listed | UBUNTU-CVE-2026-18238 |
| Ubuntu:26.04:LTS | libpcap | no fix listed | UBUNTU-CVE-2026-18238 |
| Ubuntu:26.10 | libpcap | no fix listed | UBUNTU-CVE-2026-18238 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| The Tcpdump Group | libpcap | 1.8.x1.9.x1.10.x – before 1.10.7 |
Weakness: CWE-1288, CWE-126 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N