CVE-2026-11923 Overview
CVE-2026-11923 affects IBM Security Verify Access and IBM Verify Identity Access Reverse Proxy components. In certain configurations, the Reverse Proxy performs weaker than expected cryptographic validation of user-supplied data. The weakness maps to improper authentication [CWE-287] and can undermine trust decisions the proxy makes on behalf of downstream applications.
The flaw impacts IBM Security Verify Access 10.0 through 10.0.9.2, IBM Verify Identity Access 11.0 through 11.0.3, and IBM Verify Identity Access Container 11.0 through 11.0.3. The vulnerability is network-reachable, requires no privileges, and requires no user interaction.
Critical Impact
Attackers who successfully exploit the weak cryptographic validation can bypass authentication controls, tamper with protected data, and gain unauthorized access to resources fronted by the Reverse Proxy.
Affected Products
- IBM Security Verify Access 10.0 through 10.0.9.2
- IBM Verify Identity Access 11.0 through 11.0.3
- IBM Verify Identity Access Container 11.0 through 11.0.3
Discovery Timeline
- 2026-08-12 - CVE CVE-2026-11923 published to NVD
- 2026-08-12 - Last updated in NVD database
Technical Details for CVE-2026-11923
Vulnerability Analysis
The Reverse Proxy component of IBM Security Verify Access and IBM Verify Identity Access accepts user-supplied data protected by cryptographic mechanisms. In specific configurations, the validation routine applies weaker verification than the security model requires. This weakness allows an attacker to influence values the proxy would otherwise treat as trusted.
Because the Reverse Proxy fronts protected applications, weakened validation directly translates into a broken authentication boundary [CWE-287]. Successful exploitation can expose confidential data and permit modification of application state without valid credentials.
Root Cause
The root cause is a cryptographic validation path in the Reverse Proxy that does not enforce the strength required for the data being protected. The condition depends on configuration, which explains the high attack complexity. Consult the IBM Support Page for the exact configurations and cryptographic parameters that trigger the weakness.
Attack Vector
Exploitation occurs over the network against the Reverse Proxy endpoint. The attacker crafts requests containing user-supplied data whose cryptographic protection the proxy will validate incorrectly. No authentication or user interaction is required, but the attacker must satisfy the specific configuration and cryptographic conditions that make the weak validation reachable.
No public proof-of-concept, exploit code, or CISA KEV listing exists for CVE-2026-11923 at time of publication. Refer to the IBM Support Page for authoritative technical detail.
Detection Methods for CVE-2026-11923
Indicators of Compromise
- Reverse Proxy access logs showing requests that carry cryptographically protected parameters (tokens, signed cookies, or signed headers) followed by successful backend access without a preceding valid authentication event.
- Authentication or session establishment events for identities that never completed a full login flow through IBM Security Verify Access or IBM Verify Identity Access.
- Repeated requests from a single source that vary only in cryptographic fields, indicating validation probing.
Detection Strategies
- Baseline expected token and signature formats issued by the Reverse Proxy, then alert on inbound requests that carry structurally valid but unexpected cryptographic material.
- Correlate Reverse Proxy authorization decisions with upstream identity provider events. Access decisions without a matching identity event warrant investigation.
- Review WebSEAL or Reverse Proxy configuration for any junction, authentication mechanism, or signature validation setting IBM identifies in the advisory as impacted.
Monitoring Recommendations
- Forward Reverse Proxy, WebSEAL, and container logs to a centralized analytics platform for retention and correlation.
- Monitor for anomalous rates of authentication failures immediately followed by successes from the same client.
- Track configuration drift on Reverse Proxy instances so that any change touching cryptographic validation is reviewed against the IBM advisory.
How to Mitigate CVE-2026-11923
Immediate Actions Required
- Inventory all IBM Security Verify Access 10.0.x, IBM Verify Identity Access 11.0.x, and IBM Verify Identity Access Container 11.0.x deployments.
- Apply the fixed versions published by IBM as documented on the IBM Support Page.
- Review Reverse Proxy configurations against the vulnerable configuration profile IBM describes in the advisory.
- Rotate any long-lived signed tokens, cookies, or credentials that traversed an unpatched Reverse Proxy.
Patch Information
IBM has released fixes for the affected versions. Consult the IBM Support Page for the specific fix packs and container image tags that remediate CVE-2026-11923 across IBM Security Verify Access 10.0.x, IBM Verify Identity Access 11.0.x, and IBM Verify Identity Access Container 11.0.x.
Workarounds
- Where patching is not immediately possible, reconfigure the Reverse Proxy to disable or avoid the affected cryptographic validation path as described in the IBM advisory.
- Restrict network access to the Reverse Proxy management and authentication endpoints to trusted networks.
- Increase logging verbosity on Reverse Proxy authentication and authorization decisions until the fix is applied.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
