---
id: CVE-2026-18238
title: >-
  The rpcap client code that processes a RPCAP_MSG_PACKET message received from
  the server incorrectly validates its headers
summary: >-
  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…
severity: medium
cvss: 5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N'
cwe:
  - CWE-126
  - CWE-1288
  - CWE-125
vendor: The Tcpdump Group
product: libpcap
affected:
  - libpcap 1.8.x
  - libpcap 1.9.x
  - libpcap >= 1.10.x < 1.10.7
published: '2026-09-05'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T19:20:25.117'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18238'
references:
  - url: >-
      https://github.com/the-tcpdump-group/libpcap/commit/b9590d482986d64673712460aae1d48d11fa0473
    label: security@tcpdump.org
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-18238.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-18238'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2529090'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-18238'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18238'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00179
epssPercentile: 0.06606
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-08T15:17:08.655802Z'
ingestedAt: '2026-09-06T10:53:52.033Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-09 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-18238.json)