Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
CarrierWave, a Ruby gem, versions before 1.3.2 and from 2.0.0 before 2.1.1 are affected by a server-side request forgery flaw in its remote file download feature. An attacker who can supply URLs or DNS names to that feature can make the server reach internal addresses and gather information about the internal network. Upgrade to 2.1.1 or 1.3.2. Limiting outbound network access from application servers and keeping them away from internal resources can reduce the impact.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 4.3 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.012, the 68th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 15:16 UTC First seen by agentprime
- 31 Oct 2026, 15:16 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-fwcm-636p-68r5
- OSV: GHSA-fwcm-636p-68r5
- github.com/carrierwaveuploader/carrierwave/security/advisories/GHSA-fwcm-636p-68r5
- nvd.nist.gov/vuln/detail/CVE-2021-21288
- github.com/carrierwaveuploader/carrierwave/commit/012702eb3ba1663452aa025831caa304d1a665c0
- github.com/carrierwaveuploader/carrierwave
- github.com/carrierwaveuploader/carrierwave/blob/master/CHANGELOG.md#132---2021-02-08
- github.com/carrierwaveuploader/carrierwave/blob/master/CHANGELOG.md#211---2021-02-08
- github.com/rubysec/ruby-advisory-db/blob/master/gems/carrierwave/CVE-2021-21288.yml
- rubygems.org/gems/carrierwave