CVE-2024-29041: Express.js Open Redirect in malformed URLs

First published: Mon Mar 25 2024(Updated: )

### Impact Versions of Express.js prior to 4.19.2 and pre-release alpha and beta versions before 5.0.0-beta.3 are affected by an open redirect vulnerability using malformed URLs. When a user of Express performs a redirect using a user-provided URL Express performs an encode [using `encodeurl`](https://github.com/pillarjs/encodeurl) on the contents before passing it to the `location` header. This can cause malformed URLs to be evaluated in unexpected ways by common redirect allow list implementations in Express applications, leading to an Open Redirect via bypass of a properly implemented allow list. The main method impacted is `res.location()` but this is also called from within `res.redirect()`. ### Patches https://github.com/expressjs/express/commit/0867302ddbde0e9463d0564fea5861feb708c2dd https://github.com/expressjs/express/commit/0b746953c4bd8e377123527db11f9cd866e39f94 An initial fix went out with `express@4.19.0`, we then patched a feature regression in `4.19.1` and added improved handling for the bypass in `4.19.2`. ### Workarounds The fix for this involves pre-parsing the url string with either `require('node:url').parse` or `new URL`. These are steps you can take on your own before passing the user input string to `res.location` or `res.redirect`. ### References https://github.com/expressjs/express/pull/5539 https://github.com/koajs/koa/issues/1800 https://expressjs.com/en/4x/api.html#res.location

Credit: security-advisories@github.com security-advisories@github.com

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

• agent/weakness
• agent/first-publish-date
• agent/title
• agent/type
• agent/author
• collector/nvd-api
• source/NVD
• collector/github-advisory-latest
• source/GitHub
• alias/GHSA-rv95-896h-c2vc
• alias/CVE-2024-29041
• agent/software-canonical-lookup
• collector/nvd-cve
• collector/github-advisory
• collector/epss-latest
• source/FIRST
• agent/epss
• collector/ibm-support
• source/IBM
• agent/software-canonical-lookup-request
• agent/softwarecombine
• agent/severity
• agent/description
• agent/event
• collector/mitre-cve
• source/MITRE
• agent/references
• agent/tags
• agent/last-modified-date
• collector/redhat-bugzilla
• source/Red Hat
• package-manager/npm
• vendor/ibm
• canonical/ibm planning analytics local - ibm planning analytics workspace
• version/ibm planning analytics local - ibm planning analytics workspace/2.1
• version/ibm planning analytics local - ibm planning analytics workspace/2.0