CVE-2026-44749: SAP Gateway Information Disclosure Flaw

CVE-2026-44749 Overview

CVE-2026-44749 is an information disclosure vulnerability in the SAP Gateway. Attackers can inject content into error messages, causing the application to expose request artefacts such as regex patterns and underlying Uniform Resource Identifier (URI) parsing logic. The flaw is categorized under [CWE-497]: Exposure of Sensitive System Information to an Unauthorized Control Sphere. Exploitation requires network access and low-level privileges, and impacts confidentiality only. Integrity and availability remain unaffected. SAP addressed the issue through SAP Note #3433366 published on SAP Security Patch Day.

Critical Impact

Authenticated attackers can manipulate SAP Gateway error responses to leak internal URI parsing logic and request handling artefacts, aiding reconnaissance for follow-on attacks.

Affected Products

• SAP Gateway (specific versions referenced in SAP Note #3433366)
• See SAP Note #3433366 for the authoritative product and version list
• See the SAP Security Patch Day Update for cross-referenced advisories

Discovery Timeline

• 2026-05-26 - CVE-2026-44749 published to NVD
• 2026-05-26 - Last updated in NVD database

Technical Details for CVE-2026-44749

Vulnerability Analysis

The vulnerability resides in how the SAP Gateway constructs error responses when processing inbound requests. Attacker-supplied input is reflected into error messages without sufficient sanitization or generalization. As a result, the server discloses internal artefacts that should remain server-side, including regular expression patterns used to validate request paths and structural details of the URI parser.

An authenticated attacker on the network can craft requests designed to trigger validation failures. Each crafted request yields error output that progressively reveals how the SAP Gateway parses, normalizes, and validates URIs. This information is sensitive because it exposes the internal logic an attacker would otherwise need to discover through blind probing.

The weakness maps to [CWE-497], which describes the exposure of sensitive system information to actors who should not have access to it. While the disclosure itself is low impact, the leaked parser internals can support subsequent attacks such as filter bypass, authorization routing flaws, or request smuggling against the same endpoint.

Root Cause

The SAP Gateway error handling routine includes raw configuration and parsing context, such as regex strings, in user-facing error messages. The routine fails to apply a generic error template that strips internal state before responding to the client.

Attack Vector

The attack is delivered over the network against an authenticated session. The attacker submits requests containing inputs that fail URI validation. The Gateway returns an error response containing the regex pattern or parser fragment that rejected the input, allowing the attacker to enumerate parsing rules iteratively. No user interaction is required, and the scope remains unchanged.

No verified public proof-of-concept code is available for this issue. Refer to SAP Note #3433366 for vendor-supplied technical context.

Detection Methods for CVE-2026-44749

Indicators of Compromise

• Repeated HTTP 4xx error responses from SAP Gateway endpoints originating from a single authenticated source within a short window
• Inbound requests containing malformed URI segments, unusual percent-encoding, or control characters targeting Gateway services
• Gateway error logs containing regex strings or parser context echoed back to clients

Detection Strategies

• Inspect SAP Gateway access and error logs for sequences of validation failures from the same user or session identifier
• Correlate Gateway error volume with authentication events to identify reconnaissance patterns by low-privileged accounts
• Deploy web application firewall (WAF) rules that flag responses containing regex metacharacters or parser keywords in error bodies

Monitoring Recommendations

• Forward SAP Gateway logs to a centralized analytics platform and build queries for high-rate 4xx responses per principal
• Alert on response payloads that exceed expected error message size, which may indicate verbose internal disclosure
• Track privileged and service account usage against Gateway endpoints to detect abuse of legitimate credentials

How to Mitigate CVE-2026-44749

Immediate Actions Required

• Apply SAP Note #3433366 to all affected SAP Gateway installations as a priority maintenance task
• Review SAP Gateway exposure and restrict network reachability to trusted segments and authenticated principals only
• Audit recent Gateway error logs for evidence of enumeration activity prior to patching

Patch Information

SAP released the fix as part of SAP Security Patch Day. Administrators should download and apply SAP Note #3433366 and cross-reference the SAP Security Patch Day Update for related advisories and prerequisites.

Workarounds

• Configure the SAP Gateway to return generic error messages where supported, suppressing detailed validation output
• Place the Gateway behind a reverse proxy or WAF that normalizes error responses and strips regex or parser fragments
• Restrict Gateway access to authenticated users with documented business need until the patch is deployed

# Configuration example
# Refer to SAP Note #3433366 for vendor-supplied configuration steps.
# No verified configuration snippet is published outside the SAP advisory.