Icmp — CraftedSignal Threat Feedhttps://feed.craftedsignal.io/tags/icmp/Trending threats, MITRE ATT&CK coverage, and detection metadata — refreshed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioSun, 26 Apr 2026 07:14:39 +0000CVE-2026-23398 ICMP NULL Pointer Dereferencehttps://feed.craftedsignal.io/briefs/2024-01-cve-2026-23398/Sun, 26 Apr 2026 07:14:39 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-cve-2026-23398/CVE-2026-23398 is a vulnerability related to a NULL pointer dereference in the ICMP protocol, potentially leading to a denial-of-service condition in affected Microsoft products.CVE-2026-23398 describes a NULL pointer dereference vulnerability within the icmp_tag_validation() function related to the ICMP protocol. This vulnerability, disclosed by the Microsoft Security Response Center, could be exploited by a remote attacker to trigger a denial-of-service condition on a vulnerable system. The exact mechanism involves sending crafted ICMP packets that lead to the dereferencing of a NULL pointer, causing the system to crash or become unresponsive. While specific exploitation details are not available in the provided source, the nature of the vulnerability suggests that systems processing ICMP traffic are potentially at risk. Defenders should prioritize patching systems to prevent exploitation and implement network monitoring to detect potentially malicious ICMP traffic.

Attack Chain

  1. The attacker crafts a malicious ICMP packet specifically designed to trigger the NULL pointer dereference in icmp_tag_validation().
  2. The attacker sends the crafted ICMP packet to the target system.
  3. The target system’s network stack receives the ICMP packet and processes it.
  4. During ICMP packet processing, the icmp_tag_validation() function is called to validate specific fields within the packet.
  5. The crafted ICMP packet causes icmp_tag_validation() to attempt to dereference a NULL pointer.
  6. The NULL pointer dereference causes the affected system to crash, resulting in a denial-of-service.
  7. The system becomes unresponsive, impacting availability.

Impact

Successful exploitation of CVE-2026-23398 can lead to a denial-of-service condition on the targeted system. This means the system becomes unavailable to legitimate users, potentially disrupting services and network operations. The extent of the impact depends on the role of the affected system within the network. Critical infrastructure servers or network devices are most likely to be targeted.

Recommendation

  • Apply the patch released by Microsoft to remediate CVE-2026-23398 to prevent exploitation.
  • Monitor network traffic for suspicious ICMP packets that could be indicative of exploitation attempts.
  • Deploy the Sigma rule Detect Suspicious ICMP Traffic to identify potentially malicious ICMP packets based on size and frequency.
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