CVE-2026-33658 Rails Active Storage has a possible DoS vulnerability in proxy mode via multi-range requests
Attackers can cause denial of service in Rails Active Storage proxy mode by sending HTTP requests with excessive byte ranges, consuming disproportionate CPU resources.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33658?
CVE-2026-33658 is a low-severity denial of service vulnerability in Rubyonrails Rails, published on 26 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 Active Storage's proxy controller does not limit the number of byte ranges in an HTTP Range header. A request with thousands of small ranges causes disproportionate CPU usage compared to a normal request for the same file, possibly resulting in a DoS vulnerability. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Weakness: CWE-770
Which versions are affected by CVE-2026-33658?
6 open source packages ship an affected version, including activestorage. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
activestorage RubyGems | All versions | 7.2.3.1 |
activestorage RubyGems | All versions | 7.2.3.1 |
activestorage RubyGems | From 8.0.0 | 8.0.4.1 |
activestorage RubyGems | From 8.0.0 | 8.0.4.1 |
activestorage RubyGems | From 8.1.0 | 8.1.2.1 |
activestorage RubyGems | From 8.1.0 | 8.1.2.1 |
Products include Rubyonrails Rails.
How do I fix CVE-2026-33658?
Upgrade activestorage to a fixed version for your release line: 7.2.3.1, 8.0.4.1 or 8.1.2.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33658 being exploited?
There is no known exploitation of CVE-2026-33658 in the wild and no public exploit code.
Other vulnerabilities in Rubyonrails Rails
- CVE-2013-0277 Active Record contains deserialization of arbitrary YAML
- CVE-2017-17916 SQL injection in n/a
- CVE-2017-17917 SQL injection in n/a
- CVE-2026-33195 Rails Active Storage has possible Path Traversal in DiskService
- CVE-2024-26142 Rails possible ReDoS vulnerability in Accept header parsing in Action Dispatch
Sources
Also known as DEBIAN-CVE-2026-33658, GHSA-p9fm-f462-ggrg, UBUNTU-CVE-2026-33658.