Description
Missing anchor in generated regex for rack-cors before 0.4.1 allows a malicious third-party site to perform CORS requests. If the configuration were intended to allow only the trusted example.com domain name and not the malicious example.net domain name, then example.com.example.net (as well as example.com-example.net) would be inadvertently allowed.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | ruby-rack-cors | 0.4.1-1 | — |
| Debian 13 | ruby-rack-cors | 0.4.1-1 | — |
| Debian 12 | ruby-rack-cors | 0.4.1-1 | — |
| Debian 9 | ruby-rack-cors | 0.4.0-1+deb9u1 | DSA-3931-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | ruby-rack-cors | 0.4.0-1+deb9u1build0.16.04.1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | rack-cors | < 0.4.1 | 0.4.1 | GHSA-2j9c-9vmv-7m39 |
Advisories 1
- DSA-3931-1 ruby-rack-cors - security update Debian Security (DSA / DLA) · Mar 9, 2026