Unauthenticated HMAC Replay Attack Enables Full System Compromise
CVE-2025-42959 Published on July 8, 2025

Missing Authentication check after implementation of SAP Security Note 3007182 and 3537476
An unauthenticated attacker may exploit a scenario where a Hashed Message Authentication Code (HMAC) credential, extracted from a system missing specific security patches, is reused in a replay attack against a different system. Even if the target system is fully patched, successful exploitation could result in complete system compromise, affecting confidentiality, integrity, and availability.

NVD

Vulnerability Analysis

CVE-2025-42959 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

Use of Single-factor Authentication

The use of single-factor authentication can lead to unnecessary risk of compromise when compared with the benefits of a dual-factor authentication scheme. While the use of multiple authentication schemes is simply piling on more complexity on top of authentication, it is inestimably valuable to have such measures of redundancy. The use of weak, reused, and common passwords is rampant on the internet. Without the added protection of multiple authentication schemes, a single mistake can result in the compromise of an account. For this reason, if multiple schemes are possible and also easy to use, they should be implemented and required.


Products Associated with CVE-2025-42959

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Affected Versions

SAP_SE SAP NetWeaver ABAP Server and ABAP Platform:

Exploit Probability

EPSS
0.11%
Percentile
28.59%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.