CVE-2026-45090 Dalfox: Unauthenticated Remote DoS via Closed-Channel Write in `ParameterAnalysis` (server mode)
Unauthenticated attackers can crash the Dalfox server by triggering a panic via closed-channel writes during parameter analysis.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-45090?
CVE-2026-45090 is a high-severity denial of service vulnerability in hahwul dalfox, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Dalfox is a powerful open-source XSS scanner and utility focused on automation. Prior to 2.13.0, ParameterAnalysis in pkg/scanning/parameterAnalysis.go runs two sequential worker stages that both write to the same results channel. The channel is correctly closed after the first stage completes (close(results) at line 438), but the second stage — which processes POST-body parameters (dp) — is then launched with the same already-closed channel as its output. When a scanned parameter is reflected, processParams executes results <- paramResult on the closed channel, triggering a Go runtime panic that crashes the entire dalfox process. In server mode, the crash is remotely triggerable by any unauthenticated caller who can reach the REST API, because the default configuration has no API key and the second stage activates whenever options.Data != "" (i.e., the attacker supplies the data field) and the target reflects at least one parameter. This vulnerability is fixed in 2.13.0.
Which versions are affected by CVE-2026-45090?
6 open source packages ship an affected version, including github.com/hahwul/dalfox and github.com/hahwul/dalfox/v2.
| Package | Affected | Fixed in |
|---|---|---|
github.com/hahwul/dalfox Go | All versions | None |
github.com/hahwul/dalfox Go | All versions to 1.2.2 | None |
github.com/hahwul/dalfox Go | All versions to 1.2.2 | None |
github.com/hahwul/dalfox/v2 Go | All versions | 2.13.0 |
github.com/hahwul/dalfox/v2 Go | All versions | 2.13.0 |
github.com/hahwul/dalfox/v2 Go | All versions | 2.13.0 |
How do I fix CVE-2026-45090?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-45090 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45090 exists.
Sources
Also known as GHSA-2g4x-fq3j-cgq4, GO-2026-4999.