🚨 [security] Update rack-session 2.1.0 → 2.1.1 (patch)

[depfu]

---

🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

---

Here is everything you need to know about this update. Please take a good look at what changed and the test results before merging this pull request.

What changed?

↗️ rack-session (indirect, 2.1.0 → 2.1.1) · Repo · Changelog

Security Advisories 🚨

🚨 Rack session gets restored after deletion

Summary

When using the Rack::Session::Pool middleware, simultaneous rack requests can restore a deleted rack session, which allows the unauthenticated user to occupy that session.

Details

Rack session middleware prepares the session at the beginning of request, then saves is back to the store with possible changes applied by host rack application. This way the session becomes to be a subject of race conditions in general sense over concurrent rack requests.

Impact

When using the Rack::Session::Pool middleware, and provided the attacker can acquire a session cookie (already a major issue), the session may be restored if the attacker can trigger a long running request (within that same session) adjacent to the user logging out, in order to retain illicit access even after a user has attempted to logout.

Mitigation

• Update to the latest version of rack-session, or
• Ensure your application invalidates sessions atomically by marking them as logged out e.g., using a logged_out flag, instead of deleting them, and check this flag on every request to prevent reuse, or
• Implement a custom session store that tracks session invalidation timestamps and refuses to accept session data if the session was invalidated after the request began.

Related

This code was previously part of rack in Rack < 3, see GHSA-vpfw-47h7-xj4g for the equivalent advisory in rack (affecting Rack < 3 only).

Release Notes

2.1.1

Full Changelog: v2.1.0...v2.1.1

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 2 commits:

• Bump patch version.
• Don't allow session to be recreated accidentally.

↗️ rack (indirect, 3.1.13 → 3.1.14) · Repo · Changelog

Security Advisories 🚨

🚨 Rack has an Unbounded-Parameter DoS in Rack::QueryParser

Summary

Rack::QueryParser parses query strings and application/x-www-form-urlencoded bodies into Ruby data structures without imposing any limit on the number of parameters, allowing attackers to send requests with extremely large numbers of parameters.

Details

The vulnerability arises because Rack::QueryParser iterates over each &-separated key-value pair and adds it to a Hash without enforcing an upper bound on the total number of parameters. This allows an attacker to send a single request containing hundreds of thousands (or more) of parameters, which consumes excessive memory and CPU during parsing.

Impact

An attacker can trigger denial of service by sending specifically crafted HTTP requests, which can cause memory exhaustion or pin CPU resources, stalling or crashing the Rack server. This results in full service disruption until the affected worker is restarted.

Mitigation

• Update to a version of Rack that limits the number of parameters parsed, or
• Use middleware to enforce a maximum query string size or parameter count, or
• Employ a reverse proxy (such as Nginx) to limit request sizes and reject oversized query strings or bodies.

Limiting request body sizes and query string lengths at the web server or CDN level is an effective mitigation.

Release Notes

3.1.14 (from changelog)

Security

• CVE-2025-46727 Unbounded parameter parsing in Rack::QueryParser can lead to memory exhaustion.

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 2 commits:

• Bump patch version.
• Merge commit from fork

---

Depfu will automatically keep this PR conflict-free, as long as you don't add any commits to this branch yourself. You can also trigger a rebase manually by commenting with @depfu rebase.

All Depfu comment commands

@​depfu rebase

Rebases against your default branch and redoes this update

@​depfu recreate

Recreates this PR, overwriting any edits that you've made to it

@​depfu merge

Merges this PR once your tests are passing and conflicts are resolved

@​depfu cancel merge

Cancels automatic merging of this PR

@​depfu close

Closes this PR and deletes the branch

@​depfu reopen

Restores the branch and reopens this PR (if it's closed)

@​depfu pause

Ignores all future updates for this dependency and closes this PR

@​depfu pause [minor|major]

Ignores all future minor/major updates for this dependency and closes this PR

@​depfu resume

Future versions of this dependency will create PRs again (leaves this PR as is)