# CVE-2026-55553: urllib: Cross-origin redirects preserve credential-bearing request headers, leading to potential credential leakage

> Attackers can steal sensitive credentials like API keys and cookies when urllib follows cross-origin redirects, potentially leading to account takeover.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** AZL-109529, GHSA-hq3h-g68c-hp78, ROOT-APP-NPM-CVE-2026-55553

## What is CVE-2026-55553?

CVE-2026-55553 is a high-severity vulnerability in node-modules urllib, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-522 (Insufficiently Protected Credentials), CWE-201 (Insertion of Sensitive Information Into Sent Data), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-55553?

4 open source packages ship an affected version, including urllib.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `urllib` | npm | All versions | 2.44.1 |
| `urllib` | npm | All versions | 2.44.1 |
| `urllib` | npm | From 3.0.0 | 4.9.1 |
| `urllib` | npm | From 3.0.0 | 4.9.1 |

## How do I fix CVE-2026-55553?

Upgrade urllib to a fixed version for your release line: 2.44.1 or 4.9.1.

## Is CVE-2026-55553 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55553 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-55553 and fix it if it is affected.

What it is: CVE-2026-55553 is a high-severity vulnerability in node-modules urllib, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55553 exists.

Affected packages and fixed versions:
- urllib (npm): affected all versions; fixed in 2.44.1
- urllib (npm): affected all versions; fixed in 2.44.1
- urllib (npm): affected from 3.0.0; fixed in 4.9.1
- urllib (npm): affected from 3.0.0; fixed in 4.9.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-55553/ (Markdown: https://insights.sbomify.com/CVE-2026-55553/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-55553
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-55553
- OSV: https://osv.dev/vulnerability/CVE-2026-55553

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-55553/
Summaries are generated and may contain mistakes; the official description above is the record.