Amazon Linux 2023 : libpcap, libpcap-devel (ALAS2023-2026-3100)

high Nessus Plugin ID 351073

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3100 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 detects neither reaching the end of the filter program buffer due to lack of a return instruction nor executing a jump instruction with an offset that translates to a pointer outside of the buffer. In particular uncommon use cases a crafted filter program can cause the interpreter to try reading the OS process memory in the 32GiB around the buffer on 64-bit architectures and in the entire address space on 32-bit architectures. (CVE-2026-31912)

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 'dnf update libpcap --releasever 2023.12.20260928' or or 'dnf update --advisory ALAS2023-2026-3100 --releasever 2023.12.20260928' to update your system.

Plugin Details

Severity: High

ID: 351073

File Name: al2023_ALAS2023-2026-3100.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/29/2026

Updated: 9/29/2026

Supported Sensors: Nessus Agent, Continuous Assessment, 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:2023, p-cpe:/a:amazon:linux:libpcap-debuginfo, p-cpe:/a:amazon:linux:libpcap-debugsource, 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: 9/29/2026

Vulnerability Publication Date: 9/5/2026

Reference Information

CVE: CVE-2026-0799, CVE-2026-31911, CVE-2026-31912, CVE-2026-6244, CVE-2026-6554

IAVA: 2026-A-0971

Detections

Analytics