Public proof of conceptFix available

CVE-2023-43804

Q: Is CVE-2023-43804 actively exploited?

Active exploitation of CVE-2023-43804 has not been confirmed. Its EPSS score was 1.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2023-43804?

CVE-2023-43804 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

A public proof of concept exists; no exploitation attested.

Published2023-10-04
WeaknessCWE-200

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

urllib3 is a user-friendly HTTP client library for Python. 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. This issue has been patched in urllib3 version 1.26.17 or 2.0.5.

Timeline

dates in UTC

2023-10-0417:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-43804?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-43804?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Fedoraproject fedora

Branch	Affected	Fixed in	Source
38.x	= 38	no fix published	NVD
39.x	= 39	no fix published	NVD
37.x	= 37	no fix published	NVD

Python urllib3

Branch	Affected	Fixed in	Source
2.0	≥ 2.0.0, < 2.0.6	2.0.6	NVD · OSV
1.26	< 1.26.17	1.26.17	NVD · OSV

Debian debian linux

Branch	Affected	Fixed in	Source
10.0	= 10.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

babelAlmaLinux:8all versions · fixed in 2.5.1-10.module_el8.6.0+2781+fed64c13and 1 other package
fence-agents-apcAlmaLinux:8all versions · fixed in 4.2.1-121.el8_9.2and 46 other packages
fence-virtdAlmaLinux:9all versions · fixed in 4.10.0-55.el9_3.2.alma.1and 54 other packages
python2AlmaLinux:8all versions · fixed in 2.7.18-17.module_el8.10.0+3783+2756348e.almaand 6 other packages
python2-attrsAlmaLinux:8all versions · fixed in 17.4.0-10.module_el8.6.0+2781+fed64c13
python2-backportsAlmaLinux:8all versions · fixed in 1.0-16.module_el8.6.0+2781+fed64c13
python2-backportsAlmaLinux:8all versions · fixed in 1.0-16.module_el8.6.0+3162+01a09e5a
python2-backports-ssl_match_hostnameAlmaLinux:8all versions · fixed in 3.5.0.1-12.module_el8.6.0+2781+fed64c13

89 more package ranges on OSV.dev

Vendor advisories

RHBA-2023:6852 Red Hat Product Security10 products fixed
Red Hat Bug Fix Advisory: Red Hat Quay v3.9.5 minor release

Full record on NVD

Fix

Vendor fix Red Hat Product Security RHBA-2023:6852 · 10 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround from the vendor Red Hat Product Security RHBA-2023:6852 · 10 productsMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Advisories and patches

github.comPatch
github.comPatch
github.comPatch · Vendor Advisory

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifieddeepanshu-khurana/CVE-2023-43804

Sources

CNACVSS 3.15.9read 2026-10-23
NVDCVSS 3.18.1read 2026-10-23
CNAweakness (CWE)CWE-200read 2026-10-23
FIRST EPSSEPSS score1.4 %2026-10-22
PoC-in-GitHubproof of concept1read 2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published: 2023-10-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-43804?

Is CVE-2023-43804 actively exploited?

Active exploitation of CVE-2023-43804 has not been confirmed. Its EPSS score was 1.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-43804?

CVE-2023-43804 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

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