{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64580", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.798Z", "datePublished": "2026-08-05T08:09:34.946Z", "dateUpdated": "2026-08-19T16:29:07.038Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:29:07.038Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()\n\nOn the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst()\nreleases the device reference with netdev_put() but leaves\nxdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev)\nagain, so the same net_device reference is released twice, underflowing\nits refcount (ref_tracker WARNING + \"unregister_netdevice: waiting for\n to become free\").\n\nClear xdst->u.dst.dev after the netdev_put(), the same way the XFRM\ndevice-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in\nnet/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error.\n\n ref_tracker: reference already released.\n ref_tracker: allocated in:\n xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86)\n ...\n udpv6_sendmsg (net/ipv6/udp.c:1696)\n ...\n ref_tracker: freed in:\n xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90)\n ...\n WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780\n dst_destroy (net/core/dst.c:115)\n rcu_core\n handle_softirqs\n ..." } ], "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 - The bug is reached on the local IPv6 outbound path (udpv6_sendmsg → xfrm_lookup → xfrm6_fill_dst) after configuring XFRM policy/state via netlink or IPV6_XFRM_POLICY; a remote peer cannot drive that configuration or the device state that makes in6_dev_get fail.\nAC:L - An attacker in their own netns can create interfaces, install IPv6 XFRM policy/state, generate matching UDP traffic, and concurrently drop MTU below IPV6_MIN_MTU or unregister the device to clear ip6_ptr, so they control both sides of the window that hits the error path; once entered, the double netdev_put is deterministic.\nPR:L - XFRM configuration requires CAP_NET_ADMIN via netlink_net_capable/sockopt_ns_capable, which is ns_capable() in the netns user_ns, so an unprivileged user obtains it with unshare -Urn rather than real init-namespace root.\nUI:N - No victim action is required; the attacker configures XFRM, manipulates their own netdevs, and sends packets entirely with their own processes.\nS:U - The impact is kernel net_device refcount corruption within the same host kernel authority; this is ordinary local privilege-escalation/DoS territory, not a VM escape or IOMMU/sandbox boundary cross.\nC:H - The leftover dst.dev causes a second netdev_put in dst_destroy, underflowing the net_device refcount and enabling use-after-free of the device object, which per kernel UAF guidance yields a high confidentiality/info-disclosure primitive.\nI:H - A net_device refcount underflow/UAF is heap memory corruption that can be shaped via reuse/spraying into arbitrary write or control-flow hijack, so integrity impact is high.\nA:H - Even without full exploitation, the double put triggers ref_tracker warnings and can oops/panic or hang device unregister (unregister_netdevice waiting for the device to become free), so availability impact is high." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/xfrm6_policy.c" ], "versions": [ { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "97e032e5733e49471fb73de117ea2ac1ac7c479a", "status": "affected", "versionType": "git" }, { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "df6856c2dda9187601d29b5fbd7a81b3b178cedf", "status": "affected", "versionType": "git" }, { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "43de8a49335e611adb271bbd52e84dfbc11fc185", "status": "affected", "versionType": "git" }, { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "ff636d7b7cba6dea82ecf580415ea57f2c1a11b6", "status": "affected", "versionType": "git" }, { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "e078da1b4e11390cff3201c19a9a1fe70c5b934f", "status": "affected", "versionType": "git" }, { "version": "84c4a9dfbf430861e7588d95ae3ff61535dca351", "lessThan": "136992de9bb91871084ae52d172610541c76e4d2", "status": "affected", "versionType": "git" }, { "version": "a7e22d0c0e81dde129a51ee413644124f4b59954", "status": "affected", "versionType": "git" }, { "version": "01b0d887f67a388fb2a658ee2bdd74e5ba146818", "status": "affected", "versionType": "git" }, { "version": "a98124aac0b5adc5de8ae54f11322781cb4d85c3", "status": "affected", "versionType": "git" }, { "version": "e27b7bee743d921f037b1da6f071237345bef7c1", "status": "affected", "versionType": "git" }, { "version": "3.0.79", "lessThan": "3.1", "status": "affected", "versionType": "semver" }, { "version": "3.2.46", "lessThan": "3.3", "status": "affected", "versionType": "semver" }, { "version": "3.4.46", "lessThan": "3.5", "status": "affected", "versionType": "semver" }, { "version": "3.9.3", "lessThan": "3.10", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/ipv6/xfrm6_policy.c" ], "versions": [ { "version": "3.10", "status": "affected" }, { "version": "0", "lessThan": "3.10", "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": "3.10", "versionEndExcluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.6.148" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.12.101" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.79" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2.46" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.46" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/97e032e5733e49471fb73de117ea2ac1ac7c479a" }, { "url": "https://git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf" }, { "url": "https://git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185" }, { "url": "https://git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6" }, { "url": "https://git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f" }, { "url": "https://git.kernel.org/stable/c/136992de9bb91871084ae52d172610541c76e4d2" } ], "title": "xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()", "x_generator": { "engine": "bippy-1.2.0" } } } }