{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/actors/jorge-gonz%C3%A1lez-milla/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":["Jorge González Milla"],"_cs_cpes":[],"_cs_cves":[{"id":"CVE-2026-55781"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["NanaZip (\u003c= 6.5.1742.0)"],"_cs_severities":["medium"],"_cs_tags":["dos","vulnerability","file-processing"],"_cs_type":"threat","_cs_vendors":["M2Team"],"content_html":"\u003cp\u003eNanaZip 6.5 and earlier versions contain a denial-of-service (DoS) vulnerability identified as CVE-2026-55781 within the NanaZip.Codecs UFS handler. The vulnerability exists because the application does not properly validate the fs_bsize field when parsing UFS image files. An attacker can craft a malicious UFS image file with an manipulated superblock fs_bsize value, forcing the UFS handler to perform unbounded memory allocation. This triggers excessive memory consumption, which can lead to application instability, unresponsiveness, or an immediate crash of the NanaZip process. This flaw was documented through a proof-of-concept generator that produces malformed UFS image files capable of exploiting this logic error. The issue was addressed in version 6.5.1749.0.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker creates a malformed UFS image file (e.g., poc.img) incorporating a manipulated superblock.\u003c/li\u003e\n\u003cli\u003eThe attacker modifies the fs_bsize field in the superblock to a large value (e.g., 1 GiB) within the crafted image.\u003c/li\u003e\n\u003cli\u003eThe attacker sets the root inode (di_size) to an excessively large value, such as 1 TiB, to trigger buffer overrun logic.\u003c/li\u003e\n\u003cli\u003eThe attacker delivers the malicious UFS image to a target user via email, web download, or removable media.\u003c/li\u003e\n\u003cli\u003eThe target user attempts to open or extract the malicious UFS image using NanaZip.\u003c/li\u003e\n\u003cli\u003eThe NanaZip.Codecs UFS handler processes the malformed image and reaches the vulnerable allocation routine.\u003c/li\u003e\n\u003cli\u003eThe application performs an unbounded allocation of multiple GiBs of memory based on the tainted fs_bsize value.\u003c/li\u003e\n\u003cli\u003eThe process exhausts available memory or triggers a memory management error, resulting in a denial-of-service (crash) of NanaZip.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation results in the crash and denial-of-service of the NanaZip application. While the PoC demonstrates the logic flaw, this attack requires user interaction, typically involving the opening of a malicious archive. Organizations using NanaZip to process untrusted UFS image files are at risk of application-level service disruption.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eUpdate all instances of NanaZip to version 6.5.1749.0 or later to remediate CVE-2026-55781.\u003c/li\u003e\n\u003cli\u003eIf immediate patching is not possible, implement strict file-type filtering on security gateways to block UFS image files from untrusted sources.\u003c/li\u003e\n\u003cli\u003eUse Endpoint Detection and Response (EDR) to monitor for NanaZip processes consuming excessive memory or experiencing recurring abnormal crashes.\u003c/li\u003e\n\u003c/ol\u003e\n","date_modified":"2026-08-18T14:30:04Z","date_published":"2026-08-18T14:30:04Z","id":"https://feed.craftedsignal.io/briefs/2026-08-nanazip-dos/","summary":"NanaZip 6.5 and earlier are vulnerable to a denial-of-service attack due to an unbounded memory allocation in the UFS codec handler triggered by a malicious fs_bsize value in a UFS image file.","title":"Denial of Service Vulnerability in NanaZip UFS Codec","url":"https://feed.craftedsignal.io/briefs/2026-08-nanazip-dos/"}],"language":"en","title":"CraftedSignal Threat Feed - Jorge González Milla","version":"https://jsonfeed.org/version/1.1"}