{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74562", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.916Z", "datePublished": "2026-08-15T12:28:05.154Z", "dateUpdated": "2026-08-17T05:48:41.938Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:48:41.938Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: take nh->lock for f6i_list walks in replace check and notify\n\nfib6_check_nh_list() and __nexthop_replace_notify() walk nh->f6i_list\nduring an RTNL-serialized nexthop replace without holding nh->lock. IPv6\nRTM_NEWROUTE/RTM_DELROUTE run without RTNL and mutate that list under\nnh->lock (fib6_add_rt2node_nh(), fib6_purge_rt()), so both walks race a\nconcurrent route delete that unlinks and frees a fib6_info:\n\n BUG: KASAN: slab-use-after-free in rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n Read of size 4 at addr ffff888014607e64 by task exploit/143\n rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n fib6_rt_update (net/ipv6/route.c:6412)\n __nexthop_replace_notify (net/ipv4/nexthop.c:2542)\n rtm_new_nexthop (net/ipv4/nexthop.c:2554)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\n BUG: KASAN: slab-use-after-free in fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n Read of size 8 at addr ffff888014a7d068 by task exploit/142\n fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n rtm_new_nexthop (net/ipv4/nexthop.c:2575)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nBoth walks only read the entries and take no tb6_lock, so protect them\nwith nh->lock; fib6_rt_update() uses gfp_any(), which returns GFP_ATOMIC\nunder the lock."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only via local RTNETLINK messages (RTM_NEWNEXTHOP replace and concurrent RTM_NEWROUTE/RTM_DELROUTE) sent on AF_NETLINK sockets, not by processing remote network packets.\nAC:L - An attacker can reliably trigger the race by running concurrent netlink threads that replace a nexthop while deleting IPv6 routes bound to it; both sides of the race are attacker-controlled, as demonstrated by the reported KASAN reproducers.\nPR:L - All vulnerable rtnetlink handlers require CAP_NET_ADMIN via netlink_net_capable(), which unprivileged local users can obtain inside a user/network namespace (unshare -Urn), not only real init-namespace root.\nUI:N - Exploitation requires no victim interaction beyond the attacker issuing coordinated netlink configuration commands from local processes.\nS:C - A successful UAF from CAP_NET_ADMIN inside a user/network namespace can corrupt host kernel memory and escape the container sandbox to compromise the host system.\nC:H - The race performs use-after-free reads of freed fib6_info objects (e.g., fib6_src and fib6_flags in fib6_check_nh_list and rt6_fill_node), enabling arbitrary kernel memory disclosure via heap reuse.\nI:H - Slab UAF on fib6_info during nexthop replace notification can be leveraged with heap spraying for arbitrary kernel writes and local privilege escalation to host root.\nA:H - The bug provably causes slab-use-after-free kernel oops (KASAN) during route notification and can panic or hang the system when triggered repeatedly."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/ipv4/nexthop.c"], "versions": [{"version": "081efd18326e353c6fbfdeff903a83edde953f72", "lessThan": "bb2b072c619c1f741a6234257050f72005dc63ef", "status": "affected", "versionType": "git"}, {"version": "081efd18326e353c6fbfdeff903a83edde953f72", "lessThan": "072cd1f21819dedd2252e704d255de3b0cfc61a7", "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/ipv4/nexthop.c"], "versions": [{"version": "6.16", "status": "affected"}, {"version": "0", "lessThan": "6.16", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.8", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.16", "versionEndExcluding": "7.1.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bb2b072c619c1f741a6234257050f72005dc63ef"}, {"url": "https://git.kernel.org/stable/c/072cd1f21819dedd2252e704d255de3b0cfc61a7"}], "title": "nexthop: take nh->lock for f6i_list walks in replace check and notify", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/ipv4/nexthop.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "bb2b072c619c1f741a6234257050f72005dc63ef", "status": "affected", "version": "081efd18326e353c6fbfdeff903a83edde953f72", "versionType": "git"}, {"lessThan": "072cd1f21819dedd2252e704d255de3b0cfc61a7", "status": "affected", "version": "081efd18326e353c6fbfdeff903a83edde953f72", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/ipv4/nexthop.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.16"}, {"lessThan": "6.16", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.8", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "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\nnexthop: take nh->lock for f6i_list walks in replace check and notify\n\nfib6_check_nh_list() and __nexthop_replace_notify() walk nh->f6i_list\nduring an RTNL-serialized nexthop replace without holding nh->lock. IPv6\nRTM_NEWROUTE/RTM_DELROUTE run without RTNL and mutate that list under\nnh->lock (fib6_add_rt2node_nh(), fib6_purge_rt()), so both walks race a\nconcurrent route delete that unlinks and frees a fib6_info:\n\n BUG: KASAN: slab-use-after-free in rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n Read of size 4 at addr ffff888014607e64 by task exploit/143\n rt6_fill_node.isra.0 (net/ipv6/route.c:5799)\n fib6_rt_update (net/ipv6/route.c:6412)\n __nexthop_replace_notify (net/ipv4/nexthop.c:2542)\n rtm_new_nexthop (net/ipv4/nexthop.c:2554)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\n BUG: KASAN: slab-use-after-free in fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n Read of size 8 at addr ffff888014a7d068 by task exploit/142\n fib6_check_nh_list (net/ipv4/nexthop.c:1605)\n rtm_new_nexthop (net/ipv4/nexthop.c:2575)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n\nBoth walks only read the entries and take no tb6_lock, so protect them\nwith nh->lock; fib6_rt_update() uses gfp_any(), which returns GFP_ATOMIC\nunder the lock."}], "id": "CVE-2026-74562", "lastModified": "2026-08-17T06:19:54.303", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.0, "impactScore": 6.0, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-15T13:18:01.690", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/072cd1f21819dedd2252e704d255de3b0cfc61a7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bb2b072c619c1f741a6234257050f72005dc63ef"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: nexthop: take nh->lock for f6i_list walks in replace check and notify", "id": "2517094", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2517094"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-366", "details": ["A flaw was found in the Linux kernel's nexthop component. A race condition exists where internal lists are walked without proper locking during nexthop replacement and route deletion. A local attacker could exploit this by concurrently manipulating IPv6 routes, leading to a use-after-free vulnerability. This could result in a system crash, causing a denial of service."], "name": "CVE-2026-74562", "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": "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-15T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74562\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74562\nhttps://lore.kernel.org/linux-cve-announce/2026081552-CVE-2026-74562-990d@gregkh/T"], "threat_severity": "Moderate"}