{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-5244/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[{"cvss":7.3,"id":"CVE-2026-5244"}],"_cs_exploited":false,"_cs_products":[],"_cs_severities":["high"],"_cs_tags":["cve-2026-5244","heap-based-buffer-overflow","tls-1.3","remote-code-execution"],"_cs_type":"advisory","_cs_vendors":[],"content_html":"\u003cp\u003eA heap-based buffer overflow vulnerability, identified as CVE-2026-5244, has been discovered in Cesanta Mongoose versions up to 7.20. This flaw resides within the \u003ccode\u003emg_tls_recv_cert\u003c/code\u003e function in the \u003ccode\u003emongoose.c\u003c/code\u003e file, specifically affecting the TLS 1.3 handler. The vulnerability can be triggered by manipulating the \u003ccode\u003epubkey\u003c/code\u003e argument, which leads to memory corruption. The exploit for this vulnerability is publicly available, increasing the risk of exploitation. Successful exploitation could allow a remote attacker to execute arbitrary code on the affected system. Cesanta has addressed this issue in version 7.21, with patch \u003ccode\u003e0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1\u003c/code\u003e.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker initiates a TLS 1.3 handshake with a vulnerable Mongoose server.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious TLS certificate containing an oversized \u003ccode\u003epubkey\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003emg_tls_recv_cert\u003c/code\u003e function processes the certificate.\u003c/li\u003e\n\u003cli\u003eDue to insufficient bounds checking, the oversized \u003ccode\u003epubkey\u003c/code\u003e overwrites the heap buffer.\u003c/li\u003e\n\u003cli\u003eThe heap overflow corrupts adjacent memory regions.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages memory corruption to gain control of program execution.\u003c/li\u003e\n\u003cli\u003eThe attacker injects and executes arbitrary code on the server.\u003c/li\u003e\n\u003cli\u003eThe attacker achieves complete control over the vulnerable system, potentially leading to data exfiltration or service disruption.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-5244 allows a remote attacker to execute arbitrary code on systems running vulnerable versions of Cesanta Mongoose. This could lead to complete system compromise, data breaches, and denial-of-service conditions. Given the widespread use of Mongoose in embedded systems and IoT devices, a successful attack could impact a large number of devices across various sectors.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade to Cesanta Mongoose version 7.21 or later to patch CVE-2026-5244, using the provided patch ID \u003ccode\u003e0d882f1b43ff2308b7486a56a9d60cd6dba8a3f1\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eMonitor web server logs for unusual TLS handshake patterns or certificate errors that could indicate exploitation attempts against vulnerable Mongoose instances. Utilize the provided Sigma rule to detect potential exploitation attempts.\u003c/li\u003e\n\u003cli\u003eImplement network intrusion detection systems (IDS) to detect and block malicious TLS traffic targeting vulnerable Mongoose servers.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-04-02T08:16:28Z","date_published":"2026-04-02T08:16:28Z","id":"/briefs/2026-04-mongoose-tls-overflow/","summary":"A remote heap-based buffer overflow vulnerability exists in Cesanta Mongoose versions up to 7.20 due to improper handling of the pubkey argument in the mg_tls_recv_cert function, potentially leading to code execution.","title":"Cesanta Mongoose TLS 1.3 Heap-Based Buffer Overflow Vulnerability (CVE-2026-5244)","url":"https://feed.craftedsignal.io/briefs/2026-04-mongoose-tls-overflow/"}],"language":"en","title":"CraftedSignal Threat Feed — Cve-2026-5244","version":"https://jsonfeed.org/version/1.1"}