{"id":"CVE-2026-98969","state":"PUBLISHED","title":"net/sched: em_text: reject unterminated algo before autoload","description":"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->algo, 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","publishedAt":"2026-10-23T12:19:42.012Z","updatedAt":"2026-10-30T12:40:35.763Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b62fb105961b677418cbc0a0a8837a41735729ec","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b4da5c85cd701066ff429727fb61b84bde8bcce2","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"00bcc303000bac524d62eed054d77372b38ace0f","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"22182f91c6703af6e9832cffe6d22b381031cb5a","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"85e5512369d4fe6e5f2c43712d9f9e01d4ae8437","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b627c6ba20be20334338229b4820baacb9d96826","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/em_text.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/em_text.c"]}],"references":["https://git.kernel.org/stable/c/64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb","https://git.kernel.org/stable/c/b62fb105961b677418cbc0a0a8837a41735729ec","https://git.kernel.org/stable/c/b4da5c85cd701066ff429727fb61b84bde8bcce2","https://git.kernel.org/stable/c/00bcc303000bac524d62eed054d77372b38ace0f","https://git.kernel.org/stable/c/22182f91c6703af6e9832cffe6d22b381031cb5a","https://git.kernel.org/stable/c/85e5512369d4fe6e5f2c43712d9f9e01d4ae8437","https://git.kernel.org/stable/c/b627c6ba20be20334338229b4820baacb9d96826","https://git.kernel.org/stable/c/c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021"],"weaknesses":[],"ingestedAt":"2026-10-30T13:00:06.648Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98969.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98969","state":"PUBLISHED","datePublished":"2026-10-23T12:19:42.012Z","dateUpdated":"2026-10-30T12:40:35.763Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.383Z"},"containers":{"cna":{"title":"net/sched: em_text: reject unterminated algo before autoload","descriptions":[{"lang":"en","value":"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->algo, 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"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b62fb105961b677418cbc0a0a8837a41735729ec","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b4da5c85cd701066ff429727fb61b84bde8bcce2","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"00bcc303000bac524d62eed054d77372b38ace0f","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"22182f91c6703af6e9832cffe6d22b381031cb5a","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"85e5512369d4fe6e5f2c43712d9f9e01d4ae8437","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"b627c6ba20be20334338229b4820baacb9d96826","versionType":"git"},{"version":"d675c989ed2d4ba23dff615330b04371aea83534","status":"affected","lessThan":"c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/em_text.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sched/em_text.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/64153f1dd14dabfd4e79bf506bb5b5d66f7b42eb"},{"url":"https://git.kernel.org/stable/c/b62fb105961b677418cbc0a0a8837a41735729ec"},{"url":"https://git.kernel.org/stable/c/b4da5c85cd701066ff429727fb61b84bde8bcce2"},{"url":"https://git.kernel.org/stable/c/00bcc303000bac524d62eed054d77372b38ace0f"},{"url":"https://git.kernel.org/stable/c/22182f91c6703af6e9832cffe6d22b381031cb5a"},{"url":"https://git.kernel.org/stable/c/85e5512369d4fe6e5f2c43712d9f9e01d4ae8437"},{"url":"https://git.kernel.org/stable/c/b627c6ba20be20334338229b4820baacb9d96826"},{"url":"https://git.kernel.org/stable/c/c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:40:35.763Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}