CVE-2026-55553HighMicrosoft CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Microsoft security update for CVE-2026-55553 — azl3 python-urllib3 2.0.7-6 on Azure Linux 3.0

Published
October 21, 2026
Last Modified
—

🔗 CVE IDs covered (1)

📋 Microsoft's advisory

EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55553. This page also shows what EchelonGraph holds for CVE-2026-55553, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.

🎯 Affected products1

  • azl3 python-urllib3 2.0.7-6 on Azure Linux 3.0

✅ Updates Microsoft lists: 1 update

1 row: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.

KB articleUpdateFixed build
—Security Update—

🧭 EchelonGraph on CVE-2026-55553

EchelonGraph score
7.5 HIGH
CISA KEV
Not listed
Fix status
A fix is available — apply it.

Description from the CVE record (CVE.org), as published by its numbering authority

urllib is an HTTP client for Node.js that supports authentication, redirects, timeouts, and other request features. Prior to 4.9.1 and 2.44.1, urllib follows redirects through followRedirect but reuses caller-supplied options across origins. In src/HttpClient.ts, #requestInternal recursively calls this.#requestInternal(nextUrl.href, options, requestContext), causing options.headers and auth or digestAuth values to be reused when the redirect target has a different scheme, host, or port. Authorization, Cookie, Proxy-Authorization, x-api-key, x-auth-token, and x-access-token can therefore be sent to an attacker-controlled redirected origin, exposing credentials intended for the original origin and potentially allowing reuse against the original partner API or related services. No user interaction is required. This issue is fixed in versions 2.44.1 and 4.9.1.

Published by GitHub, Inc., the CVE Numbering Authority that assigned CVE-2026-55553, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).

🔗 References (2)