CVE-2026-33174
CVE-2026-33174 — Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requests
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, when serving files through Active Storage's proxy delivery mode, the proxy controller loads the entire requested byte range into memory before sending it. A request with a large or unbounded Range header (e.g. `bytes=0-`) could cause the server to allocate memory proportional to the file size, possibly resulting in a DoS vulnerability through memory exhaustion. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Published Updated Sources: cvelistV5, GitHub_M
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
1%
chance of exploitation in 30 days
CVSS base
6.6
MEDIUM
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 6.6 | CVSS 4.0 | MEDIUM | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-789
References
7 on the record
- github.com/rails/rails/security/advisories/GHSA-r46p-8f7g-vvvg
x_refsource_CONFIRM
- github.com/rails/rails/commit/2cd933c366b777f873d4d590127da2f4a25e4ba5
x_refsource_MISC
- github.com/rails/rails/commit/42012eaaa88dfc7d0030161b2bc8074a7bbce92a
x_refsource_MISC
- github.com/rails/rails/commit/8159a9c3de3f27a2bcf2866b8bf9ceb9075e229b
x_refsource_MISC
- github.com/rails/rails/releases/tag/v7.2.3.1
x_refsource_MISC
- github.com/rails/rails/releases/tag/v8.0.4.1
x_refsource_MISC
- github.com/rails/rails/releases/tag/v8.1.2.1
x_refsource_MISC
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.