{"id":"CVE-2026-98969","summary":"net/sched: em_text: reject unterminated algo before autoload","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: em_text: reject unterminated algo before autoload\n\nThis is a follow-up to commit 9c572a83037a (\"net/sched: fix potential\nstack infoleak in em_text_dump()\"), which zero-initialised the dump-side\nstruct. Sashiko pointed at a pre-existing bug that exposed the change-side\ninput-validation gap open.\n\nem_text_change() casts the raw netlink attribute payload to struct\ntcf_em_text and passes conf-\u003ealgo, a 16-byte array with no enforced NUL\nterminator, to textsearch_prepare().  On the TS_AUTOLOAD retry\ntextsearch_prepare() calls request_module(\"ts_%s\", algo); vsnprintf()\nwalks %s until it finds a NUL, so an algo[] with no NUL reads past the\narray into the adjacent struct fields and payload and feeds those bytes\nto the usermode helper command line.  This is an out-of-bounds read and\na kernel memory disclosure.\n\nReject the attribute when no NUL exists within TC_EM_TEXT_ALGOSIZ bytes,\nmatching the check xt_string has had since 3ab720881b6e.\n\nConditions to recreate the bug:\n- CAP_NET_ADMIN on the target netns (namespace-local via unshare -Urn\n  is enough)\n- install clsact on an interface, then add a basic filter with one text\n  ematch whose algo[] is 16 bytes with no NUL (e.g. \"A\"*16) and\n  pattern_len at least 1\n- the add fails with -ENOENT and the kernel invokes modprobe with a\n  module name made of \"ts_\" plus the 16 bytes and the adjacent payload","modified":"2026-11-01T02:35:48.793473072Z","published":"2026-10-23T12:19:42.012Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98969.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/00bcc303000bac524d62eed054d77372b38ace0f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/22182f91c6703af6e9832cffe6d22b381031cb5a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/85e5512369d4fe6e5f2c43712d9f9e01d4ae8437"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b4da5c85cd701066ff429727fb61b84bde8bcce2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b627c6ba20be20334338229b4820baacb9d96826"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b62fb105961b677418cbc0a0a8837a41735729ec"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98969.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98969"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d675c989ed2d4ba23dff615330b04371aea83534"},{"fixed":"64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb"},{"fixed":"b62fb105961b677418cbc0a0a8837a41735729ec"},{"fixed":"b4da5c85cd701066ff429727fb61b84bde8bcce2"},{"fixed":"00bcc303000bac524d62eed054d77372b38ace0f"},{"fixed":"22182f91c6703af6e9832cffe6d22b381031cb5a"},{"fixed":"85e5512369d4fe6e5f2c43712d9f9e01d4ae8437"},{"fixed":"b627c6ba20be20334338229b4820baacb9d96826"},{"fixed":"c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98969.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.13"},{"fixed":"5.10.273"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.224"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.191"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.160"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.57"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98969.json"}}],"schema_version":"1.9.2"}