{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64576", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.798Z", "datePublished": "2026-08-05T08:09:32.529Z", "dateUpdated": "2026-08-19T16:28:57.222Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:28:57.222Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: initialize extack in nh_res_bucket_migrate()\n\nnh_res_bucket_migrate() passes an uninitialized netlink_ext_ack to\ncall_nexthop_res_bucket_notifiers(). When\nnh_notifier_res_bucket_info_init() fails (e.g. the kzalloc returns\n-ENOMEM), the error is propagated back before any notifier sets\nextack._msg, and the error path formats the stale pointer with\npr_err_ratelimited(\"%s\\n\", extack._msg). With CONFIG_INIT_STACK_NONE\nthis dereferences uninitialized stack memory:\n\n Oops: general protection fault, probably for non-canonical address ...\n KASAN: maybe wild-memory-access in range [...]\n RIP: 0010:string (lib/vsprintf.c:730)\n vsnprintf (lib/vsprintf.c:2945)\n _printk (kernel/printk/printk.c:2504)\n nh_res_bucket_migrate (net/ipv4/nexthop.c:1816)\n nh_res_table_upkeep (net/ipv4/nexthop.c:1866)\n rtm_new_nexthop (net/ipv4/nexthop.c:3323)\n rtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n netlink_sendmsg (net/netlink/af_netlink.c:1900)\n Kernel panic - not syncing: Fatal exception\n\nZero-initialize extack so _msg is NULL on error paths that never set it." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Triggered via local RTM_NEWNEXTHOP over rtnetlink (sendmsg → rtnetlink_rcv_msg → rtm_new_nexthop → nh_res_table_upkeep → nh_res_bucket_migrate), not by processing remote packets.\nAC:L - An attacker can create resilient nexthop groups, ensure notifiers are registered (e.g. VXLAN pernet init), force bucket migration, and induce the kzalloc -ENOMEM path; stack contents are groomable, with no attacker-independent condition required.\nPR:L - rtnetlink_rcv_msg requires CAP_NET_ADMIN via netlink_net_capable() against the socket netns user_ns, which an unprivileged user obtains with unshare -Urn, so privileges are Low not High.\nUI:N - The attacker issues the netlink nexthop configuration and triggers migration themselves; no victim action is required.\nS:U - Impact stays within the host kernel networking authority; this is a local DoS/disclosure bug, not a VM escape, IOMMU bypass, or other cross-boundary scope change.\nC:H - pr_err_ratelimited(\"%s\") dereferences an uninitialized extack._msg pointer as a C string, enabling an attacker-groomable wild kernel read into the log, consistent with treating unbounded wild/OOB reads as Confidentiality High.\nI:N - The defect only reads through the stale _msg pointer for printing; there is no write, free, or other memory-corruption integrity primitive.\nA:H - The wild %s dereference causes a general protection fault / KASAN wild-memory-access and kernel panic, as shown in the fix commit report, so Availability is High." } ] } ], "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": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "eacd2e2117e8682f937967fda1022e7f1c22d91a", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "37bbd7e1d8df0bec3d187e961783e20c30533d2c", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "c0936c131a71657afc635d0db2ab096d15d473e1", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "d536bf205c71f700f6de2086038c3e1d77724715", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "18506d7263768d76ac8e057ba55a4d9da50aad66", "status": "affected", "versionType": "git" }, { "version": "7c37c7e00411b3d1e0c5292368317aca69d1f324", "lessThan": "6347c5314cee49f364aaf2e40ff15415a57a116e", "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": "5.13", "status": "affected" }, { "version": "0", "lessThan": "5.13", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.101", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "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": "5.13", "versionEndExcluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.13", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/eacd2e2117e8682f937967fda1022e7f1c22d91a" }, { "url": "https://git.kernel.org/stable/c/37bbd7e1d8df0bec3d187e961783e20c30533d2c" }, { "url": "https://git.kernel.org/stable/c/c0936c131a71657afc635d0db2ab096d15d473e1" }, { "url": "https://git.kernel.org/stable/c/3081702ea5aca0aeed9c1ade8eadf6cde8db6b7d" }, { "url": "https://git.kernel.org/stable/c/d536bf205c71f700f6de2086038c3e1d77724715" }, { "url": "https://git.kernel.org/stable/c/18506d7263768d76ac8e057ba55a4d9da50aad66" }, { "url": "https://git.kernel.org/stable/c/6347c5314cee49f364aaf2e40ff15415a57a116e" } ], "title": "nexthop: initialize extack in nh_res_bucket_migrate()", "x_generator": { "engine": "bippy-1.2.0" } } } }