CVE-2025-54500: 
F5 BIG-IP Advanced Firewall Manager vulnerability analysis and mitigation

The HTTP/2 MadeYouReset vulnerability (CVE-2025-54500) is a critical implementation flaw in F5 BIG-IP systems that enables denial-of-service (DoS) attacks through malformed HTTP/2 control frames. The vulnerability allows attackers to bypass the typical server-imposed limit of 100 concurrent HTTP/2 requests per TCP connection, potentially leading to server resource exhaustion. This vulnerability was disclosed on August 13, 2025, and is part of a broader set of HTTP/2 implementation flaws discovered in various products (Hacker News).

The vulnerability exploits the HTTP/2 protocol's stream management mechanism by triggering server-side stream resets while maintaining valid backend processing. The attack bypasses the MAXCONCURRENTSTREAMS limit, typically set to 100, allowing attackers to create thousands of simultaneous requests. The vulnerability has received a CVSS 3.1 Base Score of 5.3 (MEDIUM) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L, and a CVSS 4.0 score of 6.9 (MEDIUM) with vector string CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N (NVD).

When exploited, the vulnerability can lead to denial-of-service conditions for legitimate users and potentially escalate into out-of-memory crashes in some vendor implementations. The attack is particularly effective due to its ability to create unbounded concurrent work on target servers while using minimal attacker resources (GBHackers).

Organizations running HTTP/2 servers should immediately review vendor advisories and apply available patches to mitigate this critical vulnerability. The vulnerability has been classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that proper resource allocation limits should be implemented as part of the mitigation strategy (NVD).

The security community has expressed significant concern about this vulnerability, with researchers noting that it could potentially surpass the impact of the devastating "Rapid Reset" attacks from 2023. The discovery has prompted immediate responses from multiple vendors, highlighting the severity of the threat (GBHackers).