Spring WebFlux Header Predicate Bypass in Pre-flight Requests

A WebFlux application using functional endpoints and deployed with DispatcherServlet may be vulnerable to a header predicate bypass in a pre-flight request. Spring Framework 7.0.0 - 7.0.8 Spring Framework 6.2.0 - 6.2.19 Spring Framework 6.1.0 - 6.1.28 Spring Framework 6.0.0 - 6.0.30 Spring Framework 5.3.0 - 5.3.49 Spring Framework 5.2.5.RELEASE - 5.2.25.RELEASE

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-2026-47892 represents a critical authorization bypass affecting multiple Spring Framework versions (5.2.5 through 7.0.8) where WebFlux applications using functional endpoints with DispatcherServlet can be exploited through malformed CORS pre-flight requests. An attacker can bypass header validation predicates by crafting specially constructed OPTIONS requests, potentially gaining unauthorized access to protected resources. This vulnerability carries a CVSS score of 9.8 (critical) and impacts organizations running Spring-based microservices and API backends across enterprise and cloud environments, particularly those relying on CORS for cross-origin communication without additional security layers.

Casky.ai's 283 mapped security skills leverage Claude AI with extended reasoning to detect exploitation patterns aligned with MITRE ATT&CK techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky will identify suspicious pre-flight request patterns—specifically anomalous OPTIONS requests with malformed or missing authentication headers, requests targeting WebFlux functional endpoints without proper CORS validation, and sequences of failed authorization attempts followed by successful resource access. The platform's skill mapping enables detection of the underlying authorization logic bypass (CWE-863) by correlating HTTP header manipulation patterns with unexpected permission grants, allowing security teams to spot attackers attempting to escalate privileges or access credentials through misconfigured endpoint predicates before exploitation occurs.

Live Threat IntelligenceComing soon

Casky Risk Score

—

EPSS Probability

—

Shodan Exposure

—

GreyNoise Signal

—

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-2026-47892.

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-2026-47892

Casky has 283 skills that investigate the attack patterns behind CVE-2026-47892. Run one and get CVSS-scored findings in 3 minutes.

Run the skill that detects this →

X Instagram LinkedIn