CVE-2026-45087: Dalfox Server Mode Vulnerable to Unauthenticated Remote Code Execution via `found-action`

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 1.4%, percentile 72: FIRST’s model estimates a 1.4% chance of exploitation activity in the next 30 days, higher than 72% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/hahwul/dalfox/v2 (Go) <= 2.12.0, fixed in 2.13.0. Check your lockfile, including transitive dependencies.

What it is

Dalfox is a powerful open-source XSS scanner and utility focused on automation. Prior to 2.13.0, when dalfox is started in REST API server mode (dalfox server), the server binds to 0.0.0.0:6664 by default and requires no API key unless the operator explicitly passes --api-key. Because model.Options — including FoundAction and FoundActionShell — is deserialized directly from attacker-supplied JSON in POST /scan, and because dalfox.Initialize explicitly propagates those two fields into the final scan options without stripping them, any unauthenticated caller who can reach the server port can supply an arbitrary shell command that the dalfox process will execute on the host whenever a scan finding is triggered. This vulnerability is fixed in 2.13.0.

From the GitHub advisory

GHSA: Unauthenticated Remote Code Execution via found-action in Dalfox Server Mode

Summary

When dalfox is started in REST API server mode (dalfox server), the server binds to 0.0.0.0:6664 by default and requires no API key unless the operator explicitly passes --api-key. Because model.Options — including FoundAction and FoundActionShell — is deserialized directly from attacker-supplied JSON in POST /scan, and because dalfox.Initialize explicitly propagates those two fields into the final scan options without stripping them, any unauthenticated caller who can reach the server port can supply an arbitrary shell command that the dalfox process will execute on the host whenever a scan finding is triggered.

Severity

Critical (CVSS 3.1: 10.0)

Weakness type: CWE-15, CWE-78, CWE-306.

Product: github.com/hahwul/dalfox/v2 (Go) · Assigned by: GitHub_M · Published: 2026-05-27

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 1.39% probability of exploitation activity in the next 30 days; percentile 72.

Timeline

• 2026-05-12 — GitHub-reviewed advisory GHSA-v25v-m36w-jp4h published (critical)
• 2026-05-27 — CVE record published by GitHub_M
• 2026-05-28 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-v25v-m36w-jp4h github.com
2. CVE.org record CVE-2026-45087 cve.org
3. NVD entry CVE-2026-45087 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical Go advisories · Today’s Security Digest