Amazon Linux 2 : libpcap (ALAS-2026-3927)

high Nessus Plugin ID 351031

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of libpcap installed on the remote host is prior to 1.5.3-11. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3927 advisory.

In BPF instructions that load/store a value from/to a scratch memory register the register index is an unsigned 32-bit integer and must not exceed 15, but libpcap BPF interpreter does not validate the value.
In particular uncommon use cases a crafted filter program can cause the interpreter to try reading and writing the OS process memory in the 16GiB starting at the current stack frame on 64-bit architectures and in the entire address space on 32-bit architectures. (CVE-2026-0799)

libpcap BPF interpreter calls abort() if it encounters a BPF instruction that has an invalid opcode. In particular uncommon use cases a crafted filter program can terminate the OS process. (CVE-2026-31911)

libpcap BPF interpreter for the 'div #k' and 'mod #k' ALU instructions does not check whether the immediate value is zero. In particular uncommon use cases a crafted filter program can cause a division by zero. (CVE-2026-6244)

libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations. In particular uncommon use cases a crafted filter program can cause the interpreter to loop infinitely. (CVE-2026-6554)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update libpcap' or or 'yum update --advisory ALAS2-2026-3927' to update your system.

Plugin Details

Severity: High

ID: 351031

File Name: al2_ALAS-2026-3927.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/29/2026

Updated: 9/29/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.27

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 6.7

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-0799

CVSS v3

Risk Factor: High

Base Score: 8.7

Temporal Score: 7.6

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:libpcap-debuginfo, p-cpe:/a:amazon:linux:libpcap-devel, p-cpe:/a:amazon:linux:libpcap

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 9/28/2026

Vulnerability Publication Date: 9/5/2026

Reference Information

CVE: CVE-2026-0799, CVE-2026-31911, CVE-2026-6244, CVE-2026-6554

IAVA: 2026-A-0971

Detections

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