CVE-2026-45089

Dalfox: Unauthenticated Arbitrary File Create/Append via `output` Option in Dalfox Server Mode

Published May 27, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
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 output, output-all, and debug fields in model.Options are JSON-tagged and deserialized directly from the attacker's request body, then propagated unchanged through dalfox.Initialize into the scan engine's logging path. The logger opens the attacker-supplied path with os.O_APPEND|os.O_CREATE|os.O_WRONLY and writes scan log lines to it. Critically, this file write block lives outside the IsLibrary guard in DalLog, so it executes even in server/library mode where file output was never intended to operate. Because no API key is required in the default configuration, an unauthenticated network caller can create or append to any file writable by the dalfox process on the host filesystem. This vulnerability is fixed in 2.13.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-8hf9-3q64-q2qf Dalfox Server Mode has an Unauthenticated Arbitrary File Create/Append via `output` Option
History
Type Values Removed Values Added
First Time appeared Hahwul
Hahwul dalfox
Vendors & Products Hahwul
Hahwul dalfox
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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 output, output-all, and debug fields in model.Options are JSON-tagged and deserialized directly from the attacker's request body, then propagated unchanged through dalfox.Initialize into the scan engine's logging path. The logger opens the attacker-supplied path with os.O_APPEND|os.O_CREATE|os.O_WRONLY and writes scan log lines to it. Critically, this file write block lives outside the IsLibrary guard in DalLog, so it executes even in server/library mode where file output was never intended to operate. Because no API key is required in the default configuration, an unauthenticated network caller can create or append to any file writable by the dalfox process on the host filesystem. This vulnerability is fixed in 2.13.0.
Title Dalfox: Unauthenticated Arbitrary File Create/Append via `output` Option in Dalfox Server Mode
Weaknesses CWE-306
CWE-434
CWE-73
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 27, 2026, 5:59 PM
Reserved
May 8, 2026, 7:27 PM
Status
Deferred
Published
May 27, 2026, 6:16 PM
Modified
Oct 26, 2026, 11:10 AM