Amazon Linux 2023 : network-flow-monitor-agent (ALAS2023-2026-3116)

high Nessus Plugin ID 351074

Synopsis

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

Description

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-3116 advisory.

libgit2 version 1.9.4 and below is vulnerable to a heap out-of-bounds read in set_data() in src/libgit2/transports/smart_pkt.c.

The vulnerable code uses a fixed-size strncmp (smart_pkt.c:239) against the unvalidated capability buffer of a smart-protocol pkt-line. When the bytes following the pkt-line in the contiguous receive buffer happen to continue with ct-format=, the comparison spuriously matches, advancing format_str past the pkt-line boundary. The following memchr(format_str, ' ', len - (format_str - line)) (smart_pkt.c:246) then underflows its size_t size argument to ~SIZE_MAX and walks the heap looking for a space byte. An unauthenticated remote attacker who controls (or man-in-the-middles) a Git server reached over HTTP/HTTPS/SSH/git:// can trigger this on the FIRST ref-pkt of the refs advertisement, before any capability negotiation has taken place. The OOB walk causes a process crash (SIGSEGV) when memchr enters an unmapped page, and -- on heap layouts where memchr finds a stray space byte before crashing -- can additionally drive the git_error_set(...'%.*s', format_len, format_str) formatter to copy a large window of heap memory into the error string. (CVE-2026-53587)

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

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

Solution

Run 'dnf update network-flow-monitor-agent --releasever 2023.12.20260928' or or 'dnf update --advisory ALAS2023-2026-3116 --releasever 2023.12.20260928' to update your system.

Plugin Details

Severity: High

ID: 351074

File Name: al2023_ALAS2023-2026-3116.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: Low

Score: 3

Percentile: 23.61

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-53587

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:network-flow-monitor-agent-debuginfo, p-cpe:/a:amazon:linux:network-flow-monitor-agent-debugsource, p-cpe:/a:amazon:linux:network-flow-monitor-agent

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: 7/23/2026

Reference Information

CVE: CVE-2026-53587

Detections

Analytics