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🛡️ CVE-2018-25091 — urllib3

⚪ Unknown ✅ No Known Exploit CWE-200 OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Authorization Header forwarded on redirect

urllib3 before 1.24.2 does not remove the authorization HTTP header when following a cross-origin redirect (i.e., a redirect that differs in host, port, or scheme). This can allow for credentials in the authorization header to be exposed to unintended hosts or transmitted in cleartext. NOTE: this issue exists because of an incomplete fix for CVE-2018-20060 (which was case-sensitive).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

CVSS metrics in full

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

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Weakness class

CVE-2018-25091 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-2018-25091 is recorded against 1 package.

  • urllib3 (fixed in 1.24.2)

Timeline and source

Published on 15 October 2023 and last revised on 10 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from OSV.

References

github.com (Fix)
github.com (Report)
github.com (Fix)
github.com (Advisory)
github.com (Fix)
github.com (Advisory)

Other advisories for this package

urllib3 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-2018-25091 on other distributions

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

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CWE CWE-200
Public Exploit ✅ No
Source OSV
Published 2023-10-15
Updated 2026-08-20
Modified 2026-06-10

Affected Packages

Software From version Fixed in
urllib3 — 1.24.2

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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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