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CVE-2024-28182 Siemens CVE debrief

CVE-2024-28182 is a denial-of-service vulnerability in the nghttp2 HTTP/2 library, affecting Siemens SINEC NMS. The nghttp2 library prior to version 1.61.0 accepts an unbounded number of HTTP/2 CONTINUATION frames even after a stream reset, causing excessive CPU consumption during HPACK header decompression. This vulnerability was published on August 13, 2024, and carries a CVSS 3.1 score of 5.3 (Medium severity). Siemens has released a vendor fix requiring update to SINEC NMS V3.0 or later. No workarounds are available for this vulnerability.

Vendor
Siemens
Product
SINEC NMS
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2024-08-13
Original CVE updated
2024-08-13
Advisory published
2024-08-13
Advisory updated
2024-08-13

Who should care

Organizations operating Siemens SINEC NMS for industrial network management, particularly those with externally accessible management interfaces. Security teams responsible for industrial control system infrastructure and OT/IT convergence environments should prioritize patching during scheduled maintenance windows.

Technical summary

The nghttp2 library implements HTTP/2 protocol handling in C. Versions prior to 1.61.0 fail to limit the number of CONTINUATION frames processed per stream, even after stream reset. This design behavior, intended to maintain HPACK context synchronization, creates a denial-of-service vector through excessive CPU consumption during header block decompression. The vulnerability affects Siemens SINEC NMS which incorporates the vulnerable nghttp2 component. Resolution requires updating to SINEC NMS V3.0 or later which contains the remediated nghttp2 v1.61.0 or equivalent fix.

Defensive priority

medium

Recommended defensive actions

  • Update Siemens SINEC NMS to version 3.0 or later to address the embedded nghttp2 vulnerability
  • Monitor for abnormal CPU utilization on systems running affected SINEC NMS versions
  • Apply network segmentation controls to limit exposure of SINEC NMS management interfaces
  • Review CISA ICS recommended practices for defense-in-depth strategies for industrial control systems

Evidence notes

The vulnerability stems from nghttp2's handling of HTTP/2 CONTINUATION frames used for HPACK context synchronization. The library continues processing these frames without limits even after stream reset, leading to resource exhaustion through excessive CPU usage during header decompression.

Official resources

2024-08-13