{"id":74640,"date":"2025-09-13T22:05:25","date_gmt":"2025-09-13T22:05:25","guid":{"rendered":""},"modified":"2025-10-01T17:01:56","modified_gmt":"2025-10-01T23:01:56","slug":"cve-2025-36854-critical-use-after-free-vulnerability-in-asp-net-leads-to-remote-code-execution","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-36854-critical-use-after-free-vulnerability-in-asp-net-leads-to-remote-code-execution\/","title":{"rendered":"CVE-2025-36854: Critical Use-After-Free Vulnerability in ASP.NET Leads to Remote Code Execution<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

Microsoft’s ASP.NET has been identified with a critical vulnerability, CVE-2025-36854, that could potentially lead to system compromise or data leakage. This vulnerability, discovered in end-of-life (EOL) versions of ASP.NET, is significant due to its potential to enable remote code execution<\/a>. It notably affects versions ASP.NET 6.0.0 to 6.0.36 and self-contained applications targeting these versions. Given the widespread usage of ASP.NET in web development, this vulnerability could potentially impact<\/a> a significant number of applications and systems.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-36854
\nSeverity: Critical, CVSS score of 8.1
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Remote Code Execution<\/a>, potential system compromise or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

ASP.NET | 6.0.0 to 6.0.36<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The vulnerability is rooted in a use-after-free error condition that occurs when closing an HTTP\/3 stream while application code<\/a> is writing to the response body. This situation creates a race condition that can lead to use-after-free, which subsequently results in remote code execution<\/a>. Essentially, the vulnerability arises from the improper handling of memory<\/a> operations, specifically, it reuses or references memory after it has been freed. Any operations performed using the original pointer become invalid, leading to the potential execution of arbitrary code<\/a>.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Below is a hypothetical example of how this vulnerability could be exploited. The example assumes an HTTP\/3 stream is being closed while application code is writing<\/a> to the response body:<\/p>\n

POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/json\n{ \"command\": \"close_http3_stream\", \"data\": \"writing to response body\" }<\/code><\/pre>\n
In this example, the malicious actor sends a POST request to close the HTTP\/3 stream while data is being written to the response body, triggering the use-after-free condition and potentially leading to remote code execution<\/a>.<\/p>\n
Recommended Mitigation<\/strong><\/p>\n
Due to the end-of-life status of the affected software components, Microsoft will not be releasing<\/a> any further updates or support. As such, users are advised to apply a vendor patch or use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary mitigation measure. Furthermore, if you’ve deployed self-contained applications targeting any of the impacted versions, these applications must be recompiled and redeployed to ensure security.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview Microsoft’s ASP.NET has been identified with a critical vulnerability, CVE-2025-36854, that could potentially lead to system compromise or data leakage. This vulnerability, discovered in end-of-life (EOL) versions of ASP.NET, is significant due to its potential to enable remote code execution. It notably affects versions ASP.NET 6.0.0 to 6.0.36 and self-contained applications targeting these versions. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[82],"product":[],"attack_vector":[80],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-74640","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft","attack_vector-rce"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t