{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98364", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.344Z", "datePublished": "2026-10-06T08:46:50.051Z", "dateUpdated": "2026-10-19T09:18:16.366Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:18:16.366Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: hold net_device reference under RCU in bundle creation\n\nxfrm_bundle_create() and xfrm_create_dummy_bundle() read dst->dev into\na local pointer without taking a device reference, then pass it to\nxfrm_fill_dst(). A concurrent RTM_DELLINK replaces dst->dev via\ndst_dev_put() and frees the old net_device, causing a use-after-free\nwhen xfrm6_fill_dst() later dereferences the stale dev pointer.\n\n BUG: KASAN: slab-use-after-free in xfrm6_fill_dst+0x82c/0x860\n (net/ipv6/xfrm6_policy.c:86 netdev_hold())\n Read of size 8 at addr ffff8880142fe588 by task exploit/153\n Call Trace:\n xfrm6_fill_dst+0x82c/0x860\n xfrm_resolve_and_create_bundle+0x21d4/0x2bd0\n xfrm_lookup_with_ifid+0x485/0x1640\n ip6_dst_lookup_flow+0x19b/0x1e0\n udpv6_sendmsg+0x1443/0x2dd0\n\nFix this by reading dst->dev via dst_dev_rcu() and keeping the RCU\nread-side critical section active until xfrm_fill_dst() has taken the\nrequired device references." } ], "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 - Both sides of the race are local syscalls: sendmsg() (udpv6_sendmsg->ip6_dst_lookup_flow->xfrm_lookup_with_ifid->xfrm_bundle_create) and an RTM_DELLINK rtnetlink request that frees the net_device. A remote peer cannot delete the link, so the network cannot cause the freed state.\nAC:L - The attacker controls both sides of the race: they repeatedly send through an xfrm-policy-matched route while deleting the link in a loop. The window between reading dst->dev and netdev_hold() in xfrm_fill_dst() is short, but the attacker can retry as often as needed.\nPR:L - xfrm_user_rcv_msg only checks netlink_net_capable(CAP_NET_ADMIN), and RTM_DELLINK is also checked per namespace. An unprivileged user with unshare -Urn can create a device, install the XFRM policy and state, and delete the device inside their own network namespace.\nUI:N - No victim action is needed: the attacker sets up the namespace, the xfrm configuration, the sending socket and the link deletion entirely on their own.\nS:U - The use-after-free is inside the kernel's own networking code and the impact stays within the kernel's security authority; no VM or IOMMU boundary is crossed.\nC:H - xfrm6_fill_dst() reads dev->ip6_ptr from the freed net_device through in6_dev_get() and stores the stale dev in a new dst. A reclaimed object controls those values, which can be used to disclose kernel memory.\nI:H - netdev_hold() increments a refcount inside the freed net_device, and in6_dev_get() increments a refcount on a pointer taken from the reclaimed object. Both are writes into attacker-reclaimable slab memory, usable to corrupt kernel data and hijack control flow.\nA:H - KASAN reports a slab-use-after-free in xfrm6_fill_dst(). On production kernels the stale dev stays attached to the new xfrm dst and is dereferenced later, which leads to an oops or panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/xfrm/xfrm_policy.c" ], "versions": [ { "version": "25ee3286dcbc830a833354bb1d15567956844813", "lessThan": "8d85d6bc9c46dc41cb2be0eac53f8ab068c3a807", "status": "affected", "versionType": "git" }, { "version": "25ee3286dcbc830a833354bb1d15567956844813", "lessThan": "9fa903b24b1f46b4ff5443bcd4aca23e5c57f9c1", "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/xfrm/xfrm_policy.c" ], "versions": [ { "version": "2.6.25", "status": "affected" }, { "version": "0", "lessThan": "2.6.25", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.8", "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": "2.6.25", "versionEndExcluding": "7.2.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.25", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/8d85d6bc9c46dc41cb2be0eac53f8ab068c3a807" }, { "url": "https://git.kernel.org/stable/c/9fa903b24b1f46b4ff5443bcd4aca23e5c57f9c1" } ], "title": "xfrm: hold net_device reference under RCU in bundle creation", "x_generator": { "engine": "bippy-1.2.0" } } } }