{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/http-request-smuggling/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"id":"CVE-2026-1502"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":[],"_cs_severities":["critical"],"_cs_tags":["crlf-injection","http-request-smuggling","proxy-vulnerability","cve"],"_cs_type":"threat","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eCVE-2026-1502 is a security vulnerability affecting Microsoft products due to insufficient validation of HTTP client proxy tunnel headers. This lack of validation allows for the potential injection of Carriage Return (CR) and Line Feed (LF) characters, which could lead to various attacks, including HTTP request smuggling and other forms of server-side injection. While specific product versions are not detailed in the initial advisory, the vulnerability\u0026rsquo;s nature suggests broad applicability across Microsoft\u0026rsquo;s HTTP client implementations. Successful exploitation could allow attackers to manipulate server responses, potentially leading to information disclosure, session hijacking, or other malicious activities. Defenders should prioritize patching and implementing detection measures to mitigate this risk.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker crafts a malicious HTTP request containing a proxy tunnel header with embedded CR/LF characters.\u003c/li\u003e\n\u003cli\u003eThe vulnerable Microsoft HTTP client processes the request and forwards it to the specified proxy server without properly sanitizing the headers.\u003c/li\u003e\n\u003cli\u003eThe proxy server interprets the injected CR/LF sequences as the end of the header section, potentially allowing the attacker to inject arbitrary HTTP headers or even a complete HTTP request.\u003c/li\u003e\n\u003cli\u003eIf the attacker injects new headers, they could modify the request\u0026rsquo;s behavior, such as setting a different Host header or injecting authentication credentials.\u003c/li\u003e\n\u003cli\u003eIf the attacker injects a complete HTTP request, they can perform HTTP request smuggling, where the proxy server processes the malicious request alongside legitimate requests.\u003c/li\u003e\n\u003cli\u003eThe smuggled request can target different resources or even internal services that are not directly accessible from the internet.\u003c/li\u003e\n\u003cli\u003eThe server processes the smuggled request, potentially executing arbitrary code or disclosing sensitive information.\u003c/li\u003e\n\u003cli\u003eThe attacker gains unauthorized access to the system or sensitive data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-1502 could lead to severe consequences, including unauthorized access to sensitive data, session hijacking, and even remote code execution. Due to the nature of HTTP request smuggling, the impact could extend beyond the initially targeted application, potentially affecting other services sharing the same infrastructure. The number of potential victims is substantial, given the widespread use of Microsoft\u0026rsquo;s HTTP client implementations.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply the security update released by Microsoft to address CVE-2026-1502 as soon as possible (reference: \u003ca href=\"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-1502)\"\u003ehttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-1502)\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Suspicious CR/LF Injection in HTTP Proxy Tunnel Headers\u0026rdquo; to identify potential exploitation attempts targeting CVE-2026-1502.\u003c/li\u003e\n\u003cli\u003eEnable detailed logging for HTTP proxy traffic to facilitate investigation of potential attacks related to CVE-2026-1502.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-26T07:36:41Z","date_published":"2026-05-26T07:36:41Z","id":"https://feed.craftedsignal.io/briefs/2026-05-crlf-injection/","summary":"CVE-2026-1502 is a critical vulnerability in Microsoft HTTP client proxy tunnel header validation, potentially allowing for CR/LF injection attacks.","title":"CVE-2026-1502 HTTP Client Proxy Tunnel Headers CR/LF Injection Vulnerability","url":"https://feed.craftedsignal.io/briefs/2026-05-crlf-injection/"}],"language":"en","title":"CraftedSignal Threat Feed — Http-Request-Smuggling","version":"https://jsonfeed.org/version/1.1"}