CVE-2026-18238 (CVSS 5)

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.

Is your site exposed to CVE-2026-18238?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.0

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0018

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-126 CWE-126

CWE-1288 CWE-1288

References

Other References

https://github.com/the-tcpdump-group/libpcap/commit/b9590d482986d64673712460aae1d48d11fa0473

Frequently Asked Questions

What is CVE-2026-18238? +

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. It has a CVSS v3.1 base score of 5.0 (MEDIUM).

How severe is CVE-2026-18238? +

CVE-2026-18238 has a CVSS v3.1 score of 5.0 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0018, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18238? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-12975

A buffer overread can occur in the CPC application when operating in full duplex SPI upon receiving an invalid packet …

CVE-2026-70652

libvips is a fast image processing library with low memory needs. Prior to version 8.18.3, libvips built with libultrahdr support …

CVE-2026-76653

A missing authentication vulnerability in the VPN configuration management has been identified in Archer MR600 (v2, v3 & v5) and …

CVE-2026-41898 9.8

rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.24 to before 0.10.78, the FFI trampolines behind SslContextBuilder::set_psk_client_callback, set_psk_server_callback, …

CVE-2017-17772 9.8

In multiple functions that process 802.11 frames, out-of-bounds reads can occur due to insufficient validation.

CVE-2024-38373 9.6

FreeRTOS-Plus-TCP is a lightweight TCP/IP stack for FreeRTOS. FreeRTOS-Plus-TCP versions 4.0.0 through 4.1.0 contain a buffer over-read issue in the …

CVE-2026-18238