Detections
Analytics
Amazon Linux 2023 : python3-urllib3 (ALAS2023-2026-3150)
medium Nessus Plugin ID 365232
Synopsis
The remote Amazon Linux 2023 host is missing a security update.Description
It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3150 advisory.urllib3 is a user-friendly HTTP client library for Python. urllib3 previously wouldn't remove the HTTP request body when an HTTP redirect response using status 301, 302, or 303 after the request had its method changed from one that could accept a request body (like `POST`) to `GET` as is required by HTTP RFCs.
Although this behavior is not specified in the section for redirects, it can be inferred by piecing together information from different sections and we have observed the behavior in other major HTTP client implementations like curl and web browsers. Because the vulnerability requires a previously trusted service to become compromised in order to have an impact on confidentiality we believe the exploitability of this vulnerability is low. Additionally, many users aren't putting sensitive data in HTTP request bodies, if this is the case then this vulnerability isn't exploitable. Both of the following conditions must be true to be affected by this vulnerability: 1. Using urllib3 and submitting sensitive information in the HTTP request body (such as form data or JSON) and 2. The origin service is compromised and starts redirecting using 301, 302, or 303 to a malicious peer or the redirected-to service becomes compromised.
This issue has been addressed in versions 1.26.18 and 2.0.7 and users are advised to update to resolve this issue. Users unable to update should disable redirects for services that aren't expecting to respond with redirects with `redirects=False` and disable automatic redirects with `redirects=False` and handle 301, 302, and 303 redirects manually by stripping the HTTP request body. (CVE-2023-45803)
urllib3 version 2.6.3 is vulnerable to a decompression bomb bypass in its streaming API (`preload_content=False`) when using Brotli support. The issue arises due to three independent code paths in `response.py` that bypass the `max_length` protection introduced in version 2.6.0 to mitigate CVE-2025-66471. Specifically, negative `max_length` values can be produced due to buffer arithmetic in `read()`, `flush_decoder` unconditionally overrides `max_length` to `-1`, and `_flush_decoder()` passes no limit at all, defaulting to unlimited decompression. This allows a malicious HTTP server to trigger an out-of-memory (OOM) condition by decompressing large payloads into memory, leading to a denial of service (DoS). The vulnerability affects urllib3 2.6.3 and Brotli 1.2.0 and impacts applications and libraries using `requests` or `urllib3` to stream content from untrusted sources. (CVE-2026-9375)
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 python-urllib3 --releasever 2023.12.20261012' or or 'dnf update --advisory ALAS2023-2026-3150 --releasever 2023.12.20261012' to update your system.See Also
https://alas.aws.amazon.com//AL2023/ALAS2023-2026-3150.html
https://alas.aws.amazon.com/faqs.html
Plugin Details
Severity: Medium
ID: 365232
File Name: al2023_ALAS2023-2026-3150.nasl
Version: 1.1
Type: Local
Agent: unix
Published: 10/12/2026
Updated: 10/12/2026
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: Low
Score: 3
Percentile: 23.69
CVSS v2
Risk Factor: Medium
Base Score: 4
Temporal Score: 3
Vector: CVSS2#AV:A/AC:H/Au:M/C:C/I:N/A:N
CVSS Score Source: CVE-2023-45803
CVSS v3
Risk Factor: Medium
Base Score: 4.2
Temporal Score: 3.7
Vector: CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
CVSS v4
Risk Factor: Medium
Base Score: 5.7
Threat Score: 1.9
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
Vulnerability Information
CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:python3-urllib3
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 10/12/2026
Vulnerability Publication Date: 10/17/2023
Reference Information
CVE: CVE-2023-45803