Internal Authentication Bypass via Request Header Manipulation

A weakness has been identified in waooAI waoowaoo up to 0.4.1. Affected by this vulnerability is the function getInternalTaskSession/getAuthSession/requireUserAuth/requireProjectAuth/requireProjectAuthLight in the library src/lib/api-auth.ts of the component Internal Task Header Handler. This manipulation of the argument x-internal-user-id request causes improper authentication. Remote exploitation of the attack is possible. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2026-15557 represents a critical authentication weakness in waooAI's internal task handling mechanisms. The vulnerability exists in the api-auth.ts library component, where improper validation of the x-internal-user-id request header allows attackers to bypass authentication controls. This flaw affects multiple authentication functions including getInternalTaskSession, getAuthSession, requireUserAuth, requireProjectAuth, and requireProjectAuthLight—essentially the core gatekeeping mechanisms that protect internal operations. With a CVSS score of 7.3, this high-severity vulnerability is particularly dangerous because it enables unauthenticated or unauthorized users to access restricted functionality and resources. Organizations using waooAI up to version 0.4.1 face significant risk, as exploitation is straightforward and proof-of-concept code is publicly available.

Casky.ai's 283 mapped security skills detect this attack pattern through Claude AI's extended reasoning applied across MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using the platform would observe detection signatures identifying suspicious patterns: unexpected manipulation of internal-user-id headers in request flows, authentication function calls with mismatched user context, and privilege escalation attempts following header injection. The system maps these indicators to CWE-287 (Improper Authentication) behaviors, surfacing findings that show lateral movement patterns where low-privilege sessions suddenly access high-privilege resources, token validation bypasses, and anomalous internal API calls. Security teams reviewing Casky findings would see correlated evidence of header-based privilege escalation attempts, allowing them to identify compromised API clients and affected user sessions before broader system compromise occurs.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-15557.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

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