CVE-2023-45803: Request body not stripped after redirect in urllib3
Noroxi assessment
Priority: Monitor (action score 16/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.59% (FIRST EPSS).
- Someone on the same network segment can trigger it. Administrator privileges are required. No user action is required. Special conditions such as timing or configuration are required.
- Fixed version: Azure Linux 3.0 ARM 2.0.7-1, 24.2-1; Azure Linux 3.0 x64 2.0.7-1, 24.2-1; CBL Mariner 2.0 ARM 1.26.18-1.
Low priority for now. Upgrade to Azure Linux 3.0 ARM 2.0.7-1, 24.2-1; Azure Linux 3.0 x64 2.0.7-1, 24.2-1; CBL Mariner 2.0 ARM 1.26.18-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- BDU:2023-06977
- GHSA-g4mx-q9vg-27p4
- ALSA-2024:0116
- ALSA-2024:0464
- ALSA-2024:11189
- ALSA-2024:11238
- ALSA-2024:2132
- ALSA-2024:2952
- ALSA-2024:2968
- DLA-3649-1
- DLA-3998-1
- openSUSE-SU-2024:13343-1
- openSUSE-SU-2026:12044-1
- openSUSE-SU-2026:12045-1
- PYSEC-2023-212
- RHBA-2024:1091
- RHBA-2024:1114
- RHBA-2024:1137
- RHBA-2024:1398
- RHBA-2024:1420
- Published
- Oct 17, 2023
- Updated
- Jun 17, 2026
- EPSS
- 0.5% · 48th percentile
- CWE
- CWE-200
Report tools
Action score
16
Monitor
Low priority for now.
- CVSS
- 16 / 40 · 4.2 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 4.2
- CNA · GitHub_M
- 4.2
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| python | urllib3 | cpe:2.3:a:python:urllib3 |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora38
- python urllib3before 1.26.18
- python urllib32.0.0 and later · before 2.0.7
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
urllib3 urllib3
- >= 2.0.0, < 2.0.7, < 1.26.18affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | fence-agents-aliyun | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-all | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-amt-ws | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-apc | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-apc-snmp | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-aws | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-azure-arm | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-bladecenter | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-brocade | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-cisco-mds | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-cisco-ucs | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-common | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-compute | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-drac5 | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-eaton-snmp | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-emerson | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-eps | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-gce | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-heuristics-ping | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-hpblade | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-ibm-powervs | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-ibm-vpc | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-ibmblade | before 4.2.1-129.el8 | 4.2.1-129.el8 |
| AlmaLinux:8 | fence-agents-ifmib | before 4.2.1-129.el8 | 4.2.1-129.el8 |
+96
Same product
python: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-20060urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e., a redirect that diff40Plan
- CVE-2026-21441urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API)36Monitor
- CVE-2026-97689urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory35Monitor
Published before and after this one in the same product
- ← EarlierCVE-2023-43804Oct 4, 2023 · `Cookie` HTTP header isn't stripped on cross-origin redirects32Monitor
- ← EarlierCVE-2018-25091Oct 15, 2023 · urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in24Monitor
- Later →CVE-2024-37891Jun 17, 2024 · Proxy-Authorization request header isn't stripped during cross-origin redirects in urllib326Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Azure Linux 3.0 ARM | 2.0.7-1 · python-urllib3 | Microsoft (MSRC) |
| Azure Linux 3.0 ARM | 24.2-1 · python-pip | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 2.0.7-1 · python-urllib3 | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 24.2-1 · python-pip | Microsoft (MSRC) |
| CBL Mariner 2.0 ARM | 1.26.18-1 · python-urllib3 | Microsoft (MSRC) |
| CBL Mariner 2.0 x64 | 1.26.18-1 · python-urllib3 | Microsoft (MSRC) |
| almalinux:fence-agents-aliyun | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-all | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-amt-ws | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-apc | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-apc-snmp | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-aws | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-azure-arm | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-bladecenter | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-brocade | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:fence-agents-cisco-mds | 4.10.0-62.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:python3-urllib3 | 1.24.2-5.el8_9.2 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python3.11-urllib3 | 1.26.12-5.el8_10 · AlmaLinux:8 | Package registry (OSV) |
| alpine:py3-urllib3 | 1.26.18-r0 · Alpine:v3.15 | Package registry (OSV) |
| debian:python-urllib3 | 1.26.12-1+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:python-urllib3 | 1.25.10-150300.4.9.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| opensuse:python-urllib3_1 | 1.26.20-7.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| PyPI:urllib3 | 1.26.18 | Package registry (OSV) |
| PyPI:urllib3 | 2.0.7 | Package registry (OSV) |
| red hat:fence-agents | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
| red hat:fence-agents-common | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
| red hat:fence-agents-compute | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
| red hat:fence-agents-debuginfo | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
| red hat:fence-agents-debugsource | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
| red hat:fence-agents-ibm-powervs | 0:4.10.0-43.el9_2.3 · Red Hat:rhel_eus:9.2::appstream | Package registry (OSV) |
+20
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone on the same network segment can trigger it.
- Administrator privileges are required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Adjacent
- Attack complexity
- High
- Privileges required
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-200 · Exposure of Sensitive Information to an Unauthorized ActorCVSS vector
CVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
nvd-primary
Root cause
The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.
The bug in code
The whole CWE-200 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
{
"permissions": ["tabs", "<all_urls>"],
"background": { "service_worker": "analytics.js" }
}Fixed
{
"permissions": ["activeTab"],
"host_permissions": ["https://yildiz.example/*"]
}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- ExcavationCAPEC-116likelihood: High · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- FootprintingCAPEC-169likelihood: High · Very Low
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- FingerprintingCAPEC-224likelihood: High · Very Low
- ICMP Echo Request PingCAPEC-285likelihood: Medium · Low
- TCP SYN ScanCAPEC-287Low
- Enumerate Mail Exchange (MX) RecordsCAPEC-290Low
ATT&CK techniques
- System Service DiscoveryT1007
- System Network Configuration DiscoveryT1016
- Remote System DiscoveryT1018
- System Owner/User DiscoveryT1033
- Masquerading: Match Legitimate Name or LocationT1036.005
- Network Service ScanningT1046
- System Network Connections DiscoveryT1049
- Process DiscoveryT1057
- Permission Groups DiscoveryT1069
- System Information DiscoveryT1082
- File and Directory DiscoveryT1083
- Account DiscoveryT1087
- Multi-Factor Authentication InterceptionT1111
- Peripheral Device DiscoveryT1120
- System Time DiscoveryT1124
- Access Token Manipulation:Token Impersonation/TheftT1134.001
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (6 more)Show less
- github.com/urllib3/urllib3/commit/4e98d57809dacab1cbe625fddeec1a290c478ea9
- github.com/urllib3/urllib3/security/advisories/GHSA-g4mx-q9vg-27p4
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5F5CUBAN5XMEBVBZPHFITBLMJV5FIJJ5/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PPDPLM6UUMN55ESPQWJFLLIZY4ZKCNRX/
- www.rfc-editor.org/rfc/rfc9110.html#name-get
- lists.debian.org/debian-lts-announce/2024/12/msg00020.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.