{"id":"CVE-2026-99037","kind":"vulnerability","aliases":["CVE-2026-99037"],"related":[],"title":"Linux kernel: dm-crypt lmk mode with AEAD ciphers crashes on load","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm-crypt: reject the lmk IV mode with AEAD ciphers\n\nA \"capi:\" table line that pairs an AEAD cipher with the lmk IV mode,\nfor example \"capi:gcm(aes)-lmk\" with the integrity:28:aead option,\ncauses an oops when it is loaded. lmk sets tfms_count to 64, but\ncrypt_alloc_tfms_aead only allocates one transform, so crypt_setkey\nreads past the end of the tfms_aead array and calls crypto_aead_setkey\non the values it finds there.\n\nlmk exists for compatibility with Loop-AES, which uses CBC, so refuse\nit with an AEAD cipher rather than allocate 64 AEAD transforms. The\ncheck cannot go in crypt_iv_lmk_ctr with the other lmk checks, because\nthe IV constructor runs after crypt_set_key.\n\nNote that this is not a security bug because the memory corruption can\nonly be triggered by root.","summary":"Loading a dm-crypt table that pairs an AEAD cipher with the lmk IV mode makes the kernel read past a transform array and oops. The kernel project states only root can trigger it, so the impact is a local crash rather than privilege gain.","severity":"low","cvss":null,"epss":0.00209,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["dm-crypt","kernel","linux","runtime","self-hosted"],"not_affected_if":["default-config","no-lmk-table","non-root-only"],"how_to_check":"- `uname -r` to see the running kernel version\n- `dmsetup table` to look for crypt targets using `capi:` ciphers with `-lmk` and an AEAD cipher such as `gcm(aes)`","fix":"- Update to a Linux kernel release that includes the upstream dm-crypt fix; the sources do not list fixed version numbers\n- Avoid `lmk` IV mode with AEAD ciphers in dm-crypt tables until patched","status":"open","published_at":"2026-10-23T13:17:26+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T04:54:17+00:00","updated_at":"2026-10-25T12:38:50+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-25T04:54:17Z","model":"claude-haiku-5-5","output":{"fix":"- Update to a Linux kernel release that includes the upstream dm-crypt fix; the sources do not list fixed version numbers\n- Avoid `lmk` IV mode with AEAD ciphers in dm-crypt tables until patched","reach":"local","title":"Linux kernel: dm-crypt lmk mode with AEAD ciphers crashes on load","impact":"low","summary":"Loading a dm-crypt table that pairs an AEAD cipher with the lmk IV mode makes the kernel read past a transform array and oops. The kernel project states only root can trigger it, so the impact is a local crash rather than privilege gain.","category":"runtime","nicknames":[],"who_cares":["linux","kernel","dm-crypt","self-hosted"],"confidence":0.6,"needs_auth":"yes","worst_case":"local root user causes a kernel oops and crash","analyst_note":"","how_to_check":"- `uname -r` to see the running kernel version\n- `dmsetup table` to look for crypt targets using `capi:` ciphers with `-lmk` and an AEAD cipher such as `gcm(aes)`","needs_analyst":false,"not_affected_if":["default-config","no-lmk-table","non-root-only"],"who_is_affected":"Only Linux hosts that create dm-crypt devices with capi AEAD ciphers and the lmk IV mode, which requires root to load. Systems that use only standard dm-crypt ciphers such as aes-xts-plain64 are not affected.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000632,"input_tokens":3560,"output_tokens":551,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-99037':16A,19A '28':119C '64':134C,188C 'ae':114C,174C 'aead':9A,38B,94C,103C,120C,139C,154C,159C,183C,189C 'alloc':137C,141C,187C 'array':52B,155C 'bug':221C 'call':157C 'cannot':193C 'capi':97C,112C 'caus':122C 'cbc':177C 'check':192C,204C 'cipher':10A,39B,95C,104C,184C 'compat':170C 'constructor':208C 'corrupt':225C 'count':132C 'crash':11A,70B 'crypt':5A,22B,33B,87C,136C,145C,196C,211C 'crypto':158C 'ctr':199C 'cve':14A,17A 'dm':4A,21B,32B,86C 'dm-crypt':3A,20B,31B,85C 'end':150C 'exampl':111C 'exist':168C 'find':165C 'follow':80C 'gain':74B 'gcm':113C 'go':194C 'host':28B 'impact':66B 'integr':118C 'iv':43B,91C,108C,197C,207C 'kernel':2A,23B,47B,56B,78C 'key':213C 'line':99C 'linux':1A,24B,77C 'lmk':6A,42B,90C,107C,115C,129C,167C,198C,203C 'load':13A,29B,128C 'local':69B 'loop':173C 'loop-a':172C 'make':45B 'memori':224C 'mode':7A,44B,92C,109C 'note':214C 'one':142C 'oop':54B,124C 'option':121C 'pair':36B,101C 'past':49B,148C 'privileg':73B 'project':57B 'rather':71B,185C 'read':48B,147C 'refus':179C 'reject':88C 'resolv':84C 'root':60B,231C 'run':209C 'runtim':25B 'secur':220C 'self':27B 'self-host':26B 'set':130C,212C 'setkey':146C,160C 'state':58B 'tabl':34B,98C 'tfms':131C,138C,153C 'transform':51B,143C,190C 'trigger':62B,229C 'use':176C 'valu':163C 'vulner':81C","nicknames":[],"mitigations":[],"who_affected":"Only Linux hosts that create dm-crypt devices with capi AEAD ciphers and the lmk IV mode, which requires root to load. Systems that use only standard dm-crypt ciphers such as aes-xts-plain64 are not affected.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T13:17:26+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-99037","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99037","severity":null,"published_at":"2026-10-23T13:17:26+00:00","modified_at":"2026-10-23T13:17:26+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+00:00","note":null},{"source":"epss","external_id":"CVE-2026-99037","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-99037","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:50+00:00","fetched_at":"2026-10-25T12:38:50+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"}