Detections
Analytics

Azure Linux 3.0 Security Update: fluent-bit (CVE-2025-31498)

high Nessus Plugin ID 296060

Language:

Synopsis

The remote Azure Linux host is missing one or more security updates.

Description

The version of fluent-bit installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2025-31498 advisory.

 - c-ares is an asynchronous resolver library. From 1.32.3 through 1.34.4, there is a use-after-free in read_answers() when process_answer() May re-enqueue a query either due to a DNS Cookie Failure or when the upstream server does not properly support EDNS, or possibly on TCP queries if the remote closed the connection immediately after a response. If there was an issue trying to put that new transaction on the wire, it would close the connection handle, but read_answers() was still expecting the connection handle to be available to possibly dequeue other responses. In theory a remote attacker might be able to trigger this by flooding the target with ICMP UNREACHABLE packets if they also control the upstream nameserver and can return a result with one of those conditions, this has been untested. Otherwise only a local attacker might be able to change system behavior to make send()/write() return a failure condition. This vulnerability is fixed in 1.34.5. (CVE-2025-31498)

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

Solution

Update the affected packages.

See Also

https://nvd.nist.gov/vuln/detail/CVE-2025-31498

Plugin Details

Severity: High

ID: 296060

File Name: azure_linux_CVE-2025-31498.nasl

Version: 1.1

Type: local

Published: 1/22/2026

Updated: 1/22/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.7

CVSS v2

Risk Factor: Medium

Base Score: 6.6

Temporal Score: 4.9

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

CVSS Score Source: CVE-2025-31498

CVSS v3

Risk Factor: High

Base Score: 7

Temporal Score: 6.1

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

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

CVSS v4

Risk Factor: High

Base Score: 8.3

Threat Score: 4.9

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: p-cpe:/a:microsoft:azure_linux:fluent-bit-debuginfo, p-cpe:/a:microsoft:azure_linux:fluent-bit-devel, p-cpe:/a:microsoft:azure_linux:fluent-bit, x-cpe:/o:microsoft:azure_linux

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

Exploit Ease: No known exploits are available

Patch Publication Date: 4/8/2025

Vulnerability Publication Date: 4/8/2025

Reference Information

CVE: CVE-2025-31498