Spring Security Authorization Server Unencoded HTML Rendering

Spring Security Authorization Server's default consent page renders user-controlled values without HTML entity encoding. Spring Security 7.1.0 Spring Security 7.0.0 - 7.0.6

Casky was already ahead

This CVE exploits attack patterns that Casky's 323matched 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-2026-47877 is a Cross-Site Scripting (CWE-79) vulnerability in Spring Security's default consent page that fails to HTML entity-encode user-controlled input before rendering it to browsers. This affects Spring Security versions 7.1.0 and 7.0.0 through 7.0.6, making any organization using these versions as their authorization server vulnerable to XSS attacks. An attacker can inject malicious scripts through OAuth consent flows, potentially stealing session tokens, hijacking user accounts, or redirecting victims to phishing sites. Organizations relying on Spring Security for identity and access management are particularly at risk, as the consent page is often the final step before users grant permission to third-party applications.

Casky's 323 mapped security skills leverage Claude's extended reasoning to detect the attack patterns underlying this vulnerability across MITRE ATT&CK techniques TA0001 (Initial Access) and TA0043 (Reconnaissance). Practitioners using Casky would identify suspicious consent page parameters that contain script tags, encoded payloads, or event handler attributes—indicators of TA0001 exploitation attempts. The platform's skills would simultaneously flag reconnaissance activities (TA0043) where attackers probe the authorization endpoint for encoding weaknesses or test XSS payloads. Through Claude's contextual analysis, practitioners would see findings that correlate unencoded output patterns with malicious input, map the attack chain from initial parameter injection through payload execution, and receive prioritized alerts on exploitation attempts before compromise occurs—enabling proactive patching and WAF rule deployment.

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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 →

323 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-47877.

Abuse of Public-Facing API: Mobile API Abuse

mobile security · low

Run

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

MITRE ATT&CK Techniques

TA0001 TA0043

Investigate the attack patterns behind CVE-2026-47877

Casky has 323 skills that investigate the attack patterns behind CVE-2026-47877. Run one and get CVSS-scored findings in 3 minutes.

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