# CVE-2026-109805: SAP NetWeaver HMAC cryptography weakness in RFC callback

Source: https://junglewise.ai/threats/cve-2026-109805-due-to-a-weak-hmac-cryptography-calculation-when-receiving-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-109805 · Severity: medium · CVSS 6.4 · Published 2026-11-10

SAP NetWeaver and ABAP Platform use weak HMAC cryptography when processing RFC (Remote Function Call) callbacks between application servers. An authenticated attacker with network access between servers could intercept and modify communication to impersonate other callers, executing unauthorized functions with escalated privileges and compromising the confidentiality, integrity, and availability of the entire SAP system.

Technologies: [SAP ABAP Platform](https://junglewise.ai/threats/technologies/sap-abap-platform), [SAP NetWeaver](https://junglewise.ai/threats/technologies/netweaver). Vendors: [SAP](https://junglewise.ai/threats/vendors/sap).

## Quick answers

**Is CVE-2026-109805 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109805 being exploited in the wild.

**How severe is CVE-2026-109805?** Medium severity, with a CVSS score of 6.4, published 10 November 2026.

**Which products and versions are affected?** SAP NetWeaver; SAP ABAP Platform.

**Is there a fix for CVE-2026-109805?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-109805 attacked?** It is attacked over the network or from the adjacent network, in a hosted service.

**Am I affected by CVE-2026-109805?** Check whether you run SAP ABAP Platform or SAP NetWeaver. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the RFC callback handling logic where insufficient HMAC validation allows an attacker to forge caller identity in inter-server communication. An authenticated attacker positioned on a network segment between application servers can intercept, modify, and replay RFC callbacks to execute functions as a different user with higher privileges. The weakness in cryptographic calculation undermines the security model protecting remote function invocations.

## Affected products

- SAP NetWeaver
- SAP ABAP Platform

## Timeline

- 2026-11-10: disclosed

## References

- [https://me.sap.com/notes/3786876](https://me.sap.com/notes/3786876)
- [https://url.sap/sapsecuritypatchday](https://url.sap/sapsecuritypatchday)

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- [SAP NetWeaver ABAP RFC protocol memory corruption](https://junglewise.ai/threats/cve-2026-76966-due-to-improper-rfc-protocol-validation-in-the-sap-kernel-used-by)
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