CVE-2023-45803

Sensitive request-body disclosure via redirected GET

Published Oct 17, 2023 · Updated Nov 3, 2025

Information disclosure in urllib3 before 1.26.18 and 2.0.0 through 2.0.6 allows attackers to expose request-body data via redirects. In connectionpool.urlopen and poolmanager.urlopen, HTTP 303 handling changes POST to GET but retains the body and content headers for the redirected request. Exposure requires sensitive body data and either a compromised origin that issues the redirect or a compromised redirect destination.

CVSS severity4.2
Medium
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in urllib3 before 1.26.18 and 2.0.0 through 2.0.6 allows attackers to expose request-body data via redirects. In connectionpool.urlopen and poolmanager.urlopen, HTTP 303 handling changes POST to GET but retains the body and content headers for the redirected request. Exposure requires sensitive body data and either a compromised origin that issues the redirect or a compromised redirect destination.

The record

CVE
CVE-2023-45803
Published
Oct 17, 2023
Updated
Nov 3, 2025
Vendor
urllib3
Product
urllib3
Classifications
CWE-200
Attack vector
adjacent
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.26.18
  2. Affected versionversion=>= 2.0.0, < 2.0.7

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesUnavailable in this record.

What is affected?

urllib3 · urllib3version=< 1.26.18; version=>= 2.0.0, < 2.0.7

Published CVSS scores

4.2NISTCVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
4.2GitHubCVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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