{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-68323", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.382Z", "datePublished": "2026-08-10T12:02:59.034Z", "dateUpdated": "2026-08-13T22:43:20.362Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-13T22:43:20.362Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: serialize udp bearer replicast list updates\n\ntipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with\nlist_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs\nfrom the encap receive softirq (via tipc_udp_rcast_disc()) without\nrtnl_lock(), so it can race the cleanup delete and corrupt the list:\n\n list_del corruption. prev->next should be ffff8880298d7ab8,\n but was ffff88802449ad38. (prev=ffff888027e3ec98)\n kernel BUG at lib/list_debug.c:62!\n RIP: __list_del_entry_valid_or_report+0x17a/0x200\n Workqueue: events cleanup_bearer\n Call Trace:\n cleanup_bearer (net/tipc/udp_media.c:811)\n process_one_work (kernel/workqueue.c:3302)\n worker_thread (kernel/workqueue.c:3466)\n\nThe bearer can be enabled from an unprivileged user namespace, as the\nTIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM.\n\nAdd a spinlock to struct udp_bearer and take it around the list_add_rcu()\nin tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so\nthe two writers can no longer corrupt the list.\n\nReject a duplicate peer under the same lock before allocating, and remove\ntipc_udp_is_known_peer(). The old lockless pre-check in\ntipc_udp_rcast_disc() was racy: two softirqs discovering the same peer\ncould both find it absent and add it twice.\n\ncleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the\nbearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add()\nand add a peer after cleanup_bearer() has already emptied the list, leaking\nthat entry when the bearer is freed. Mark the bearer disabled under\nrcast_lock once the list is emptied and refuse further additions."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Exploitation requires the local half of the race \u2014 enabling and then disabling a TIPC UDP replicast bearer via generic netlink \u2014 even though the second half is driven by UDP packets; a purely remote peer cannot schedule cleanup_bearer(), so local access is needed.\nAC:L - The attacker owns both racers: they flood LINK_CONFIG UDP packets at the bearer port (softirq list_add_rcu) while issuing TIPC_NL_BEARER_DISABLE (workqueue list_del_rcu), and the window is wide because b->up is cleared before cleanup_bearer is scheduled, so it can be retried until it hits.\nPR:L - TIPC_NL_BEARER_ENABLE/DISABLE/ADD use GENL_UNS_ADMIN_PERM, i.e. CAP_NET_ADMIN in the net's owning user namespace, which any unprivileged user obtains with unshare -Urn; no real root is required.\nUI:N - The attacker performs every step itself \u2014 create netns, enable bearer, send packets, disable bearer \u2014 with no action by any other user or administrator.\nS:U - The corruption and any resulting escalation stay within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Concurrent list_add_rcu/list_del_rcu on ub->rcast.list leaves dangling and duplicated entries, so udp_replicast objects freed by rcast_free_rcu remain reachable from the list; the resulting use-after-free reads of attacker-groomed heap memory can disclose arbitrary kernel data.\nI:H - List corruption makes list_add_rcu/list_del_rcu write prev->next and next->prev through stale pointers into freed or attacker-controlled heap memory, a classic write primitive that is leverageable for control-flow hijack and privilege escalation.\nA:H - The reported symptom is a hard kernel BUG at lib/list_debug.c:62 (__list_del_entry_valid_or_report) in the cleanup_bearer workqueue, i.e. an immediate panic; without CONFIG_DEBUG_LIST the corrupted list and freed-entry traversal crash the kernel anyway."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/tipc/udp_media.c"], "versions": [{"version": "ef20cd4dd1633987bcf46ac34ace2c8af212361f", "lessThan": "d70c81001df9320d3445e664428a1d408b5ba896", "status": "affected", "versionType": "git"}, {"version": "ef20cd4dd1633987bcf46ac34ace2c8af212361f", "lessThan": "350e592ff4e30e48ffb55e142d11a73e63f4869c", "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/tipc/udp_media.c"], "versions": [{"version": "4.9", "status": "affected"}, {"version": "0", "lessThan": "4.9", "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": "4.9", "versionEndExcluding": "7.1.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "7.2-rc5"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d70c81001df9320d3445e664428a1d408b5ba896"}, {"url": "https://git.kernel.org/stable/c/350e592ff4e30e48ffb55e142d11a73e63f4869c"}], "title": "tipc: serialize udp bearer replicast list updates", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/tipc/udp_media.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d70c81001df9320d3445e664428a1d408b5ba896", "status": "affected", "version": "ef20cd4dd1633987bcf46ac34ace2c8af212361f", "versionType": "git"}, {"lessThan": "350e592ff4e30e48ffb55e142d11a73e63f4869c", "status": "affected", "version": "ef20cd4dd1633987bcf46ac34ace2c8af212361f", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/tipc/udp_media.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.9"}, {"lessThan": "4.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.6", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2-rc5", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: serialize udp bearer replicast list updates\n\ntipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with\nlist_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs\nfrom the encap receive softirq (via tipc_udp_rcast_disc()) without\nrtnl_lock(), so it can race the cleanup delete and corrupt the list:\n\n list_del corruption. prev->next should be ffff8880298d7ab8,\n but was ffff88802449ad38. (prev=ffff888027e3ec98)\n kernel BUG at lib/list_debug.c:62!\n RIP: __list_del_entry_valid_or_report+0x17a/0x200\n Workqueue: events cleanup_bearer\n Call Trace:\n cleanup_bearer (net/tipc/udp_media.c:811)\n process_one_work (kernel/workqueue.c:3302)\n worker_thread (kernel/workqueue.c:3466)\n\nThe bearer can be enabled from an unprivileged user namespace, as the\nTIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM.\n\nAdd a spinlock to struct udp_bearer and take it around the list_add_rcu()\nin tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so\nthe two writers can no longer corrupt the list.\n\nReject a duplicate peer under the same lock before allocating, and remove\ntipc_udp_is_known_peer(). The old lockless pre-check in\ntipc_udp_rcast_disc() was racy: two softirqs discovering the same peer\ncould both find it absent and add it twice.\n\ncleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the\nbearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add()\nand add a peer after cleanup_bearer() has already emptied the list, leaking\nthat entry when the bearer is freed. Mark the bearer disabled under\nrcast_lock once the list is emptied and refuse further additions."}], "id": "CVE-2026-68323", "lastModified": "2026-08-13T23:17:30.137", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-10T13:20:22.443", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/350e592ff4e30e48ffb55e142d11a73e63f4869c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d70c81001df9320d3445e664428a1d408b5ba896"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: TIPC denial of service due to race condition in UDP bearer list updates", "id": "2513243", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2513243"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-820", "details": ["In the Linux kernel, the following vulnerability has been resolved:\ntipc: serialize udp bearer replicast list updates\ntipc_udp_rcast_add() and cleanup_bearer() both update ub->rcast.list with\nlist_add_rcu() / list_del_rcu(), but nothing serializes them. The add runs\nfrom the encap receive softirq (via tipc_udp_rcast_disc()) without\nrtnl_lock(), so it can race the cleanup delete and corrupt the list:\nlist_del corruption. prev->next should be ffff8880298d7ab8,\nbut was ffff88802449ad38. (prev=ffff888027e3ec98)\nkernel BUG at lib/list_debug.c:62!\nRIP: __list_del_entry_valid_or_report+0x17a/0x200\nWorkqueue: events cleanup_bearer\nCall Trace:\ncleanup_bearer (net/tipc/udp_media.c:811)\nprocess_one_work (kernel/workqueue.c:3302)\nworker_thread (kernel/workqueue.c:3466)\nThe bearer can be enabled from an unprivileged user namespace, as the\nTIPCv2 generic-netlink ops carry no GENL_ADMIN_PERM.\nAdd a spinlock to struct udp_bearer and take it around the list_add_rcu()\nin tipc_udp_rcast_add() and the list_del_rcu() loop in cleanup_bearer() so\nthe two writers can no longer corrupt the list.\nReject a duplicate peer under the same lock before allocating, and remove\ntipc_udp_is_known_peer(). The old lockless pre-check in\ntipc_udp_rcast_disc() was racy: two softirqs discovering the same peer\ncould both find it absent and add it twice.\ncleanup_bearer() runs from a workqueue after tipc_udp_disable() clears the\nbearer's up bit, so an encap softirq can still reach tipc_udp_rcast_add()\nand add a peer after cleanup_bearer() has already emptied the list, leaking\nthat entry when the bearer is freed. Mark the bearer disabled under\nrcast_lock once the list is emptied and refuse further additions.", "A flaw was found in the Linux kernel's TIPC (Transparent Inter-Process Communication) module. A race condition exists in the handling of UDP bearer replicast list updates. This can occur when `tipc_udp_rcast_add()` and `cleanup_bearer()` functions attempt to update the list concurrently without proper serialization. An unprivileged local user can exploit this flaw to trigger a kernel bug, leading to a system crash and a denial of service."], "name": "CVE-2026-68323", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux_nvidia:", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux for NVIDIA 26"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-10T12:02:59Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-68323\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-68323\nhttps://git.kernel.org/stable/c/350e592ff4e30e48ffb55e142d11a73e63f4869c\nhttps://git.kernel.org/stable/c/d70c81001df9320d3445e664428a1d408b5ba896"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ef20cd4dd1633987bcf46ac34ace2c8af212361f,d70c81001df9320d3445e664428a1d408b5ba896)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ef20cd4dd1633987bcf46ac34ace2c8af212361f,350e592ff4e30e48ffb55e142d11a73e63f4869c)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.6,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2-rc5,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-10T16:00:04.017868+00:00", "updated": "2026-08-14T00:45:17.209300+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}