CVE-2026-40988
HIGHAn application using spring-security-saml2-service-provider and the REDIRECT binding for SAML 2.0 Login or Logout may be vulnerable to a denial of service by way of an unbounded writer…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
An application using spring-security-saml2-service-provider and the REDIRECT binding for SAML 2.0 Login or Logout may be vulnerable to a denial of service by way of an unbounded writer that inflates the compressed SAML payload into memory.
Affected versions: Spring Security 5.7.0 through 5.7.23; 5.8.0 through 5.8.25; 6.3.0 through 6.3.16; 6.4.0 through 6.4.16; 6.5.0 through 6.5.10; 7.0.0 through 7.0.5.
Affected Products
spring securityvmwareDetection & mitigation playbook
Vendor / applianceDetect
Inventory every vmware spring security deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the vmware spring security security patch or hotfix for CVE-2026-40988 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-40988 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2026-40988. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40988 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-40988 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.