Unauthenticated Portfolio Access via Missing ID Validation

The GET /api/v1/public/:accessId/portfolio endpoint in ghostfolio accepts private access IDs without validating granteeUserId filtering, allowing unauthenticated access to full portfolio data. Attackers with a private access ID can retrieve sensitive portfolio information including holdings, quantities, buy prices, and performance metrics without authentication.

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

Ghostfolio's API endpoint fails to properly validate user permissions when accessing private portfolio data through access IDs, enabling unauthenticated attackers to retrieve complete portfolio information including holdings, quantities, cost basis, and performance metrics. This authorization bypass (CWE-862) affects any organization or individual using Ghostfolio for sensitive financial tracking, wealth management platforms, and investment monitoring services. The vulnerability is particularly dangerous because it exposes granular financial data—such as asset allocation, purchase prices, and transaction history—that could be weaponized for targeted phishing, social engineering, or competitive intelligence attacks.

Casky's skill set detects the attack patterns underlying this vulnerability by mapping to MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). When analyzing this CVE, practitioners using Casky would identify findings related to broken access control patterns—specifically how attackers leverage valid-but-unvalidated access identifiers to escalate from unauthenticated to privileged information access. The 283 matching skills enable detection of reconnaissance activity (adversaries probing for valid access IDs), unauthorized API enumeration, and data exfiltration attempts. Practitioners would see Casky flag suspicious sequential API calls requesting portfolio endpoints with varying access IDs, unusual data volumes being retrieved without authentication, and patterns consistent with systematic credential enumeration—all indicators of exploitation against this authorization weakness.

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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-2026-59708.

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

Investigate the attack patterns behind CVE-2026-59708

Casky has 283 skills that investigate the attack patterns behind CVE-2026-59708. Run one and get CVSS-scored findings in 3 minutes.

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