CVE-2026-18238Network attack vector

Client memory exposure via RPCAP header mismatch

Published Sep 5, 2026 · Updated Sep 8, 2026

Buffer over-read in libpcap 1.8.x, 1.9.x, and 1.10.x before 1.10.7 allows remote attackers to trigger an out-of-bounds read via RPCAP. The pcap_read_nocb_remote() routine neither requires a complete RPCAP_MSG_PACKET header nor subtracts that header when validating caplen against the general payload. Exposure requires non-default remote-capture support and an attacker-controlled RPCAP server; a crafted response places up to 20 bytes of adjacent client memory in captured-packet data.

CVSS severity5.0
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in libpcap 1.8.x, 1.9.x, and 1.10.x before 1.10.7 allows remote attackers to trigger an out-of-bounds read via RPCAP. The pcap_read_nocb_remote() routine neither requires a complete RPCAP_MSG_PACKET header nor subtracts that header when validating caplen against the general payload. Exposure requires non-default remote-capture support and an attacker-controlled RPCAP server; a crafted response places up to 20 bytes of adjacent client memory in captured-packet data.

The record

CVE
CVE-2026-18238
Published
Sep 5, 2026
Updated
Sep 8, 2026
Vendor
The Tcpdump Group
Product
libpcap
Classifications
CWE-1288, CWE-126
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.10.x <1.10.7
  2. Affected versionversion=1.8.x
  3. Affected versionversion=1.9.x

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Tcpdump Group · libpcapversion=1.10.x <1.10.7; version=1.8.x; version=1.9.x

Published CVSS scores

5.0The Tcpdump GroupCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1288Improper Validation of Consistency within Input
CWE-126Buffer Over-read

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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