{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-68138", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.370Z", "datePublished": "2026-08-10T11:59:01.744Z", "dateUpdated": "2026-08-10T11:59:01.744Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-10T11:59:01.744Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: serialize qdisc_rtab_list against concurrent get/put\n\nqdisc_get_rtab() and qdisc_put_rtab() mutate the process-global singly\nlinked list qdisc_rtab_list and a plain non-atomic 'int refcnt' with no\nlock. This was only safe because every caller historically held the RTNL\nmutex, which serialized all rate-table lookups, inserts and frees.\n\nThat invariant no longer holds. cls_flower sets\nTCF_PROTO_OPS_DOIT_UNLOCKED, so tc_new_tfilter() keeps rtnl_held == false\nfor it and sets TCA_ACT_FLAGS_NO_RTNL. That flag propagates through\ntcf_exts_validate_ex() -> tcf_action_init() -> tcf_action_init_1() ->\ntcf_police_init(), which calls qdisc_get_rtab()/qdisc_put_rtab() with the\nRTNL mutex NOT held. Two RTM_NEWTFILTER requests on different CPUs, each\nadding a flower filter with a police action carrying the same rate, then\nrace on qdisc_rtab_list and on the non-atomic refcnt, leading to a\nuse-after-free / double-free of the kmalloc-2k struct qdisc_rate_table.\nqdisc_rtab_list is a single global (not per-netns), so the corrupted\nobject is shared system-wide.\n\n BUG: KASAN: slab-use-after-free in qdisc_put_rtab+0x12f/0x160\n qdisc_put_rtab+0x12f/0x160\n tcf_police_init+0xda9/0x1590\n tcf_action_init_1+0x460/0x6b0\n tcf_action_init+0x439/0xa40\n tcf_exts_validate_ex+0x42d/0x550\n fl_change+0xddd/0x7da0\n tc_new_tfilter+0xaa7/0x2420\n rtnetlink_rcv_msg+0x95e/0xe90\n which belongs to the cache kmalloc-2k of size 2048\n\nProtect qdisc_rtab_list and the refcount with a dedicated spinlock. The\n(sleeping, GFP_KERNEL) allocation in qdisc_get_rtab() is performed before\ntaking the lock; if a concurrent inserter added an identical table in the\nmeantime the freshly allocated one is freed under the lock, so no\nduplicate is leaked. qdisc_put_rtab() now decrements the refcount and\nunlinks under the same lock."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/sch_api.c"], "versions": [{"version": "470502de5bdb1ed0def643a4458593a40b8f6b66", "lessThan": "fb29e1b41052488ee3f2d115d4a870497ebd7f7d", "status": "affected", "versionType": "git"}, {"version": "470502de5bdb1ed0def643a4458593a40b8f6b66", "lessThan": "f43ee0c0730d6191629b5ee1ceae27b1ebfdc047", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/sch_api.c"], "versions": [{"version": "5.1", "status": "affected"}, {"version": "0", "lessThan": "5.1", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2-rc5", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.1.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.1", "versionEndExcluding": "7.2-rc5"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/fb29e1b41052488ee3f2d115d4a870497ebd7f7d"}, {"url": "https://git.kernel.org/stable/c/f43ee0c0730d6191629b5ee1ceae27b1ebfdc047"}], "title": "net/sched: serialize qdisc_rtab_list against concurrent get/put", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{}

{}

{"created": "2026-08-10T14:15:03.850566+00:00", "updated": "2026-08-10T14:15:03.850572+00:00", "vendors": [], "weaknesses": ["CWE-416", "CWE-415", "CWE-362"]}