{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-99033", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.387Z", "datePublished": "2026-10-23T12:21:37.662Z", "dateUpdated": "2026-10-23T12:21:37.662Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-23T12:21:37.662Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/packet: guard the ll header push in packet_rcv_spkt()\n\npacket_rcv_spkt() restores the link layer header with\n\n\tskb_push(skb, skb->data - skb_mac_header(skb));\n\nThat subtraction is only meaningful when the device actually has a link\nlayer header. packet_rcv() and tpacket_rcv() both wrap it in\ndev_has_header(), which is also the predicate the block comment at the\ntop of the file states the restore in terms of; packet_rcv_spkt() does\nnot. commit d549699048b4 (\"net/packet: fix packet receive on L3\ndevices without visible hard header\") introduced the helper and changed\nthe two call sites, and this one stayed behind.\n\nA device without a visible ll header can leave skb->mac_header at the\n0xFFFF sentinel that __alloc_skb() initialises it to. A CAN skb does:\ninit_can_skb() sets pkt_type and ip_summed but does not reset the\nheaders, and commit 9f10374bb024 (\"can: remove private CAN skb\nheadroom infrastructure\") dropped the skb_reset_*_header() calls that\nused to be there. skb_mac_header() is then 0xFFFF, the length becomes\na large negative number and skb_push() reports it through\nskb_under_panic() -- from softirq context, so it is a full system panic\neven with panic_on_oops=0:\n\n skbuff: skb_under_panic: text:ffffffff8bd21bc1 len:-65455 put:-65471 head:... data:... tail:0x50 end:0x180 dev:can0\n kernel BUG at net/core/skbuff.c:214!\n RIP: 0010:skb_panic+0x50/0x60\n Call Trace:\n \n skb_push+0x38/0x40\n packet_rcv_spkt+0xe1/0x170\n __netif_receive_skb_core.constprop.0+0x7e8/0xd30\n ...\n Kernel panic - not syncing: Fatal exception in interrupt\n\nThe socket type is reachable: packet_create() accepts SOCK_PACKET\nalongside SOCK_RAW and SOCK_DGRAM behind the same CAP_NET_RAW check,\nand neither the socket length nor a capability check keeps it away\nfrom a CAN interface.\n\nThe missing skb_reset_*_header() calls in init_can_skb() are a\nregression in their own right and are being fixed separately, but a\npacket socket should not turn a link layer that did not initialise its\nmac header into a kernel panic. Guard the push the way the other two\nreceive paths do.\n\nTested on v7.3-rc5 under QEMU with a slcan device on a pty, which is\nthe driver RX path: vcan does not reproduce it, because can_send()\nresets the headers on the way out. One SOCK_PACKET socket bound to\ncan0 and one frame written into the line discipline panics an\nunpatched kernel with the trace above; the same image with this patch\nprints no panic and powers off normally. Both kernels are this tree,\ndefconfig plus CONFIG_CAN_SLCAN=y, differing only in this hunk." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/packet/af_packet.c" ], "versions": [ { "version": "d549699048b4b5c22dd710455bcdb76966e55aa3", "lessThan": "d8a24b9e1774a93943caf68d48c5e17be432220b", "status": "affected", "versionType": "git" }, { "version": "d549699048b4b5c22dd710455bcdb76966e55aa3", "lessThan": "31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be", "status": "affected", "versionType": "git" }, { "version": "d549699048b4b5c22dd710455bcdb76966e55aa3", "lessThan": "3efe0e0944157fdd2072b4dc7eb0491a317ed272", "status": "affected", "versionType": "git" }, { "version": "d549699048b4b5c22dd710455bcdb76966e55aa3", "lessThan": "00fbf71e74115f7628fc0880b855434b1e70c40c", "status": "affected", "versionType": "git" }, { "version": "d549699048b4b5c22dd710455bcdb76966e55aa3", "lessThan": "28bc1ef699610ee09ce3d46a00552f5a0a0144bd", "status": "affected", "versionType": "git" }, { "version": "dadddde259a19105ee69e788835f4d4552767aa9", "status": "affected", "versionType": "git" }, { "version": "5.9.13", "lessThan": "5.10", "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/packet/af_packet.c" ], "versions": [ { "version": "5.10", "status": "affected" }, { "version": "0", "lessThan": "5.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.113", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.11", "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": "5.10", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.12.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "7.2.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d8a24b9e1774a93943caf68d48c5e17be432220b" }, { "url": "https://git.kernel.org/stable/c/31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be" }, { "url": "https://git.kernel.org/stable/c/3efe0e0944157fdd2072b4dc7eb0491a317ed272" }, { "url": "https://git.kernel.org/stable/c/00fbf71e74115f7628fc0880b855434b1e70c40c" }, { "url": "https://git.kernel.org/stable/c/28bc1ef699610ee09ce3d46a00552f5a0a0144bd" } ], "title": "net/packet: guard the ll header push in packet_rcv_spkt()", "x_generator": { "engine": "bippy-1.2.0" } } } }