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CVE-2026-55553VulnerabilityPublished Updated

Microsoft · urllib: Cross-origin redirects preserve credential-bearing request headers, leading to potential credential leakage

Affects MicrosoftSource GCVE Database

0
Authoritative record:CVE-2026-55553· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 4.9.1 or 2.44.1 soon.

Data as of 28 Oct 2026, 09:42 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 4.9.1, 2.44.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade urllib to 4.9.1 or 2.44.1.

Affected software

ProductAffectedFixed in
node-modulesurllibAffected
  • >=3.0.0 <4.9.1
Fixed in
  • 4.9.1
node-modulesurllibAffected
  • <2.44.1
Fixed in
  • 2.44.1

AI-suggested

If you cannot patch yet, users should exercise caution when handling redirects with urllib, especially in cross-origin scenarios involving sensitive credentials.

Description

A vulnerability in urllib version 3.0 allows cross-origin redirects to preserve credential-bearing request headers, which can lead to potential credential leakage.

References

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