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🛡️ CVE-2023-43804 — debian-linux

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-200 NVD
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Cookie HTTP header isn't stripped on cross-origin redirects

urllib3 doesn't treat the Cookie HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a Cookie header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly.

Users must handle redirects themselves instead of relying on urllib3's automatic redirects to achieve safe processing of the Cookie header, thus we decided to strip the header by default in order to further protect users who aren't using the correct approach.

Affected usages

We believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited:

  • Using an affected version of urllib3 (patched in v1.26.17 and v2.0.6)
  • Using the Cookie header on requests, which is mostly typical for impersonating a browser.
  • Not disabling HTTP redirects
  • Either not using HTTPS or for the origin server to redirect to a malicious origin.

Remediation

  • Upgrading to at least urllib3 v1.26.17 or v2.0.6
  • Disabling HTTP redirects using redirects=False when sending requests.
  • Not using the Cookie header.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs administrative privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: High — administrative rights are needed first.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Weakness class

CVE-2023-43804 is classified as CWE-200: Exposure of Sensitive Information. Information that should stay internal is disclosed to someone who is not authorised to see it.

Affected software

CVE-2023-43804 is recorded against 3 packages.

  • debian-linux
  • fedora
  • urllib3 (from 2.0.0 up to 1.26.17)

Timeline and source

Published on 4 October 2023 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
github.com
github.com
lists.debian.org
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
github.com
github.com
github.com
lists.debian.org
lists.debian.org
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
security.netapp.com
www.vicarius.io

Other advisories for this package

debian-linux has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-200: Exposure of Sensitive Information) in other software:

CVE-2023-43804 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 8.0
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N
CWE CWE-200
Public Exploit ✅ No
Source NVD
Published 2023-10-04
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
debian-linux
fedora
urllib3 2.0.0 1.26.17

References

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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