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CVE-2026-66768NVD status: Awaiting Analysis

SAP NetWeaver (SAP GUI for Java): Reliance on Untrusted Inputs in a Security Decision

Published Updated By the CyberSecBulletin desk

CVE-2026-66768 is a critical-severity reliance on untrusted inputs in a security decision vulnerability in SAP NetWeaver (SAP GUI for Java) from SAP, with a CVSS 3.1 base score of 9.0 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, but only if a user takes part, for example by opening a link or file. Affected SAP NetWeaver (SAP GUI for Java) versions: BC-FES-JAV 8.10. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of SAP NetWeaver (SAP GUI for Java) you run against the affected versions below, and install the vendor's latest release.
  2. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
SAPSAP NetWeaver (SAP GUI for Java)BC-FES-JAV 8.10Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H. Scored by CNA (sap.com).

Official description

SAP GUI for Java does not correctly enforce the trust level policy for certain functions invoked from a connected backend system. A low-privileged attacker could exploit this weakness by manipulating a connected backend system to trigger affected functionality. This could allow arbitrary command execution on the victim's machine, leading to a high impact on the confidentiality, integrity, and availability of the affected system.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Reliance on Untrusted Inputs in a Security Decision

The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

How developers prevent this class of flaw

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. With a stateless protocol such as HTTP, use a framework that maintains the state for you. Examples include ASP.NET View State and the OWASP ESAPI Session Management feature. Be careful of language features that provide state support, since these might be provided as a convenience to the programmer and may not be considering security.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

More Reliance on Untrusted Inputs in a Security Decision vulnerabilities (CWE-807)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Reliance on Untrusted Inputs in a Security Decision vulnerabilities

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