{"id":"CVE-2026-58829","kind":"vulnerability","aliases":["CVE-2026-58829"],"related":[],"title":"Linux FUSE: use-after-free in backing mmap lets local users escalate privileges","description":"In fuse_backing_mmap of backing.c, there is a possible memory corruption due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.","summary":"A use-after-free in the FUSE backing-file mmap path (fuse_backing_mmap in backing.c) causes memory corruption. A local user with no extra privileges can use it to escalate to higher privileges.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["fuse","infrastructure","kernel","linux"],"not_affected_if":["no-untrusted-local-users"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-02T20:17:47+00:00","first_seen_at":"2026-11-02T20:35:31+00:00","triaged_at":"2026-11-02T20:39:08+00:00","updated_at":"2026-11-02T20:39:08+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-02T20:39:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux FUSE: use-after-free in backing mmap lets local users escalate privileges","impact":"high","summary":"A use-after-free in the FUSE backing-file mmap path (fuse_backing_mmap in backing.c) causes memory corruption. A local user with no extra privileges can use it to escalate to higher privileges.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["linux","kernel","fuse"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"local user gains elevated privileges on the machine","analyst_note":"Check the kernel fix commit and affected version ranges for fuse_backing_mmap in backing.c; NVD entry has no CVSS or version data yet.","how_to_check":"unknown","plain_action":"","needs_analyst":true,"not_affected_if":["no-untrusted-local-users"],"who_is_affected":"Systems running a kernel with the FUSE backing-file feature where local users can run code. The sources do not list affected kernel versions or whether the feature must be enabled. Systems without untrusted local users are lower risk.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000631,"input_tokens":4086,"output_tokens":445,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':16A,19A '-58829':17A,20A 'addit':89C 'back':8A,34B,39B,63C 'backing-fil':33B 'backing.c':42B,66C 'caus':43B 'corrupt':45B,72C 'could':80C 'cve':15A,18A 'due':73C 'escal':13A,57B,84C 'execut':90C 'exploit':99C 'extra':51B 'file':35B 'free':6A,29B,78C 'fuse':2A,21B,32B,38B,62C 'higher':59B 'infrastructur':22B 'interact':94C 'kernel':23B 'lead':81C 'let':10A 'linux':1A,24B 'local':11A,47B,83C 'memori':44B,71C 'mmap':9A,36B,40B,64C 'need':92C,97C 'path':37B 'possibl':70C 'privileg':14A,52B,60B,86C,91C 'use':4A,27B,54B,76C 'use-after-fre':3A,26B 'user':12A,48B,93C","nicknames":[],"mitigations":[],"who_affected":"Systems running a kernel with the FUSE backing-file feature where local users can run code. The sources do not list affected kernel versions or whether the feature must be enabled. Systems without untrusted local users are lower risk.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["fuse","infrastructure","kernel","linux","unknown"],"first_public_at":"2026-11-02T20:17:47+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-58829","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-58829","severity":null,"published_at":"2026-11-02T20:17:47+00:00","modified_at":"2026-11-02T20:17:47+00:00","first_seen_at":"2026-11-02T20:35:31+00:00","fetched_at":"2026-11-02T20:35:31+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}