CVE-2026-33658lowCWE-770

Rails Active Storage has a possible DoS vulnerability in proxy mode via multi-range requests

8Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 2.3epss 0.4%

exploitation probability

0.4%top 64% of all CVEs

observed exploitation

nono source reports it

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.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U

Affected products

rails · activestorage

References

https://github.com/rails/rails/releases/tag/v7.2.3.1 https://github.com/rails/rails/releases/tag/v8.0.4.1 https://github.com/rails/rails/releases/tag/v8.1.2.1 https://github.com/rails/rails/security/advisories/GHSA-p9fm-f462-ggrg https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-33658.yml