{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98598", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.359Z", "datePublished": "2026-10-18T15:19:11.126Z", "dateUpdated": "2026-10-19T09:22:24.055Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:22:24.055Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: Prevent rt6_insert_exception() for dying fib6_info.\n\nBefore the cited commit, fib6_nh_flush_exceptions() always set\nfrom->exception_bucket_flushed = 1 under rt6_exception_lock to\nprevent rt6_insert_exception() from inserting a new exception\nfor a dying fib6_info.\n\nThe flag was replaced with the FIB6_EXCEPTION_BUCKET_FLUSHED\nbit stored in nh->rt6i_exception_bucket.\n\nThe problem is that now the bit is only set when the bucket\nis not NULL and fib6_nh_flush_exceptions() is called from\nfib6_nh_release() after fib6_ref has already reached zero.\n\nIf rt6_insert_exception() is called while the target fib6_info\nis being removed via fib6_purge_rt(), a new exception could be\ncreated successfully because rt6_flush_exceptions() no longer\nsets the bit.\n\nThis creates a reference cycle between the fib6_info and the\nexception route, leaking the fib6_info, its nexthop device,\nand all per-CPU routes in fib6_nh->rt6i_pcpu, which stalls netdev\nunregistration.\n\n[ 34.680602] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 44.920675] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 55.176582] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n\nLet's call fib6_drop_pcpu_from() before rt6_flush_exceptions(),\nto set fib6_destroying before rt6_exception_lock, and check\nf6i->fib6_destroying in rt6_insert_exception().\n\nNote that FIB6_EXCEPTION_BUCKET_FLUSHED logic is dead and\nwe can clean it up in net-next."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv6/ip6_fib.c", "net/ipv6/route.c"], "versions": [{"version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "lessThan": "649ffc76ed5483b2caf35ed90d3787538efc4e53", "status": "affected", "versionType": "git"}, {"version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "lessThan": "e03e77071e75ce726d877f0a4349a28b6e1f487a", "status": "affected", "versionType": "git"}, {"version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "lessThan": "0346ec2f080b40d95ed05b853bb9226289e75212", "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/ipv6/ip6_fib.c", "net/ipv6/route.c"], "versions": [{"version": "5.3", "status": "affected"}, {"version": "0", "lessThan": "5.3", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.55", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.9", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "5.3", "versionEndExcluding": "6.18.55"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.2.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.3", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/649ffc76ed5483b2caf35ed90d3787538efc4e53"}, {"url": "https://git.kernel.org/stable/c/e03e77071e75ce726d877f0a4349a28b6e1f487a"}, {"url": "https://git.kernel.org/stable/c/0346ec2f080b40d95ed05b853bb9226289e75212"}], "title": "ipv6: Prevent rt6_insert_exception() for dying fib6_info.", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv6/ip6_fib.c", "net/ipv6/route.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "649ffc76ed5483b2caf35ed90d3787538efc4e53", "status": "affected", "version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "versionType": "git"}, {"lessThan": "e03e77071e75ce726d877f0a4349a28b6e1f487a", "status": "affected", "version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "versionType": "git"}, {"lessThan": "0346ec2f080b40d95ed05b853bb9226289e75212", "status": "affected", "version": "cc5c073a693fa6ed7a207b0436114f68cce72434", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv6/ip6_fib.c", "net/ipv6/route.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.3"}, {"lessThan": "5.3", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.55", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "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\nipv6: Prevent rt6_insert_exception() for dying fib6_info.\n\nBefore the cited commit, fib6_nh_flush_exceptions() always set\nfrom->exception_bucket_flushed = 1 under rt6_exception_lock to\nprevent rt6_insert_exception() from inserting a new exception\nfor a dying fib6_info.\n\nThe flag was replaced with the FIB6_EXCEPTION_BUCKET_FLUSHED\nbit stored in nh->rt6i_exception_bucket.\n\nThe problem is that now the bit is only set when the bucket\nis not NULL and fib6_nh_flush_exceptions() is called from\nfib6_nh_release() after fib6_ref has already reached zero.\n\nIf rt6_insert_exception() is called while the target fib6_info\nis being removed via fib6_purge_rt(), a new exception could be\ncreated successfully because rt6_flush_exceptions() no longer\nsets the bit.\n\nThis creates a reference cycle between the fib6_info and the\nexception route, leaking the fib6_info, its nexthop device,\nand all per-CPU routes in fib6_nh->rt6i_pcpu, which stalls netdev\nunregistration.\n\n[ 34.680602] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 44.920675] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 55.176582] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n\nLet's call fib6_drop_pcpu_from() before rt6_flush_exceptions(),\nto set fib6_destroying before rt6_exception_lock, and check\nf6i->fib6_destroying in rt6_insert_exception().\n\nNote that FIB6_EXCEPTION_BUCKET_FLUSHED logic is dead and\nwe can clean it up in net-next."}], "id": "CVE-2026-98598", "lastModified": "2026-10-19T10:19:21.240", "metrics": {}, "published": "2026-10-18T16:17:12.500", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0346ec2f080b40d95ed05b853bb9226289e75212"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/649ffc76ed5483b2caf35ed90d3787538efc4e53"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e03e77071e75ce726d877f0a4349a28b6e1f487a"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ipv6: Prevent rt6_insert_exception() for dying fib6_info", "id": "2554961", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2554961"}, "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-772", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nipv6: Prevent rt6_insert_exception() for dying fib6_info.\nBefore the cited commit, fib6_nh_flush_exceptions() always set\nfrom->exception_bucket_flushed = 1 under rt6_exception_lock to\nprevent rt6_insert_exception() from inserting a new exception\nfor a dying fib6_info.\nThe flag was replaced with the FIB6_EXCEPTION_BUCKET_FLUSHED\nbit stored in nh->rt6i_exception_bucket.\nThe problem is that now the bit is only set when the bucket\nis not NULL and fib6_nh_flush_exceptions() is called from\nfib6_nh_release() after fib6_ref has already reached zero.\nIf rt6_insert_exception() is called while the target fib6_info\nis being removed via fib6_purge_rt(), a new exception could be\ncreated successfully because rt6_flush_exceptions() no longer\nsets the bit.\nThis creates a reference cycle between the fib6_info and the\nexception route, leaking the fib6_info, its nexthop device,\nand all per-CPU routes in fib6_nh->rt6i_pcpu, which stalls netdev\nunregistration.\n[ 34.680602] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 44.920675] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\n[ 55.176582] unregister_netdevice: waiting for gre6 to become free. Usage count = 68\nLet's call fib6_drop_pcpu_from() before rt6_flush_exceptions(),\nto set fib6_destroying before rt6_exception_lock, and check\nf6i->fib6_destroying in rt6_insert_exception().\nNote that FIB6_EXCEPTION_BUCKET_FLUSHED logic is dead and\nwe can clean it up in net-next.", "A flaw was found in the Linux kernel's IPv6 networking subsystem. A local attacker or network traffic triggering route exceptions while an IPv6 route is being removed can cause a circular reference leak. This failure to release resources prevents network devices from unregistering, resulting in stalled operations and a Denial of Service (DoS)."], "name": "CVE-2026-98598", "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": "Out of support scope", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "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:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-18T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98598\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98598\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98598.mbox"], "threat_severity": "Moderate"}