net/packet: guard the ll header push in packet_rcv_spkt()
In the Linux kernel, the following vulnerability has been resolved: net/packet: guard the ll header push in packet_rcv_spkt() packet_rcv_spkt() restores the link layer header with skb_push(skb, skb->data - skb_mac_header(skb)); That subtraction is only meaningful when the device actually has a link layer header. packet_rcv() and tpacket_rcv() both wrap it in dev_has_header(), which is also the predicate the block comment at the top of the file states the restore in terms of; packet_rcv_spkt() does not. commit d549699048b4 ("net/packet: fix packet receive on L3 devices without visible hard header") introduced the helper and changed the two call sites, and this one stayed behind. A device without a visible ll header can leave skb->mac_header at the 0xFFFF sentinel that __alloc_skb() initialises it to. A CAN skb does: init_can_skb() sets pkt_type and ip_summed but does not reset the headers, and commit 9f10374bb024 ("can: remove private CAN skb headroom infrastructure") dropped the skb_reset_*_header() calls that used to be there. skb_mac_header() is then 0xFFFF, the length becomes a large negative number and skb_push() reports it through skb_under_panic() -- from softirq context, so it is a full system panic even with panic_on_oops=0: skbuff: skb_under_panic: text:ffffffff8bd21bc1 len:-65455 put:-65471 head:... data:... tail:0x50 end:0x180 dev:can0 kernel BUG at net/core/skbuff.c:214! RIP: 0010:skb_panic+0x50/0x60 Call Trace: skb_push+0x38/0x40 packet_rcv_spkt+0xe1/0x170 __neti
CVE-2026-99033
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-99033
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "d549699048b4b5c22dd710455bcdb76966e55aa3",
"lessThan": "d8a24b9e1774a93943caf68d48c5e17be432220b",
"versionType": "git"
},
{
"status": "affected",
"version": "d549699048b4b5c22dd710455bcdb76966e55aa3",
"lessThan": "31c7b15b3716e8d0dad58d2c3cdf321dfd06f4be",
"versionType": "git"
},
{
"status": "affected",
"version": "d549699048b4b5c22dd710455bcdb76966e55aa3",
"lessThan": "3efe0e0944157fdd2072b4dc7eb0491a317ed272",
"versionType": "git"
},
{
"status": "affected",
"version": "d549699048b4b5c22dd710455bcdb76966e55aa3",
"lessThan": "00fbf71e74115f7628fc0880b855434b1e70c40c",
"versionType": "git"
},
{
"status": "affected",
"version": "d549699048b4b5c22dd710455bcdb76966e55aa3",
"lessThan": "28bc1ef699610ee09ce3d46a00552f5a0a0144bd",
"versionType": "git"
},
{
"status": "affected",
"version": "dadddde259a19105ee69e788835f4d4552767aa9",
"versionType": "git"
},
{
"status": "affected",
"version": "5.9.13",
"lessThan": "5.10",
"versionType": "semver"
}
],
"programFiles": [
"net/packet/af_packet.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.10"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.10",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.11",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/packet/af_packet.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-99033
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #52866 · Revision 1
- Added to Heist Feed
- Publisher date