Vulnerability · Published Aug 6, 2025 · Assigned by Go
CVE-2025-47908Denial of service via malicious preflight requests in github.com/rs/cors
High 7.5
In plain English
A high-severity security flaw in github.com/rs/cors from github.com/rs/cors. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 49.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Middleware causes a prohibitive amount of heap allocations when processing malicious preflight requests that include a Access-Control-Request-Headers (ACRH) header whose value contains many commas. This behavior can be abused by attackers to produce undue load on the middleware/server as an attempt to cause a denial of service.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/rs/cors | 1.11.0 | GHSA-mh55-gqvf-xfwm |
| Go | github.com/rs/cors | 1.11.0 | GO-2024-2883 |
| Ubuntu:22.04:LTS | golang-github-rs-cors | no fix listed | UBUNTU-CVE-2025-47908 |
| Ubuntu:24.04:LTS | golang-github-rs-cors | no fix listed | UBUNTU-CVE-2025-47908 |
| Ubuntu:25.10 | golang-github-rs-cors | no fix listed | UBUNTU-CVE-2025-47908 |
| Ubuntu:26.04:LTS | golang-github-rs-cors | no fix listed | UBUNTU-CVE-2025-47908 |
| Ubuntu:26.10 | golang-github-rs-cors | no fix listed | UBUNTU-CVE-2025-47908 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| github.com/rs/cors | github.com/rs/cors | 1.9.0 – before 1.11.0 |