net: gro: fix double aggregation of flush-marked skbs
In the Linux kernel, the following vulnerability has been resolved: net: gro: fix double aggregation of flush-marked skbs Commit 0ab03f353d36 ("net-gro: Fix GRO flush when receiving a GSO packet.") added a flush check to skb_gro_receive(), but skb_gro_receive_list() lacks the same validation. As a result, packets marked with NAPI_GRO_CB(skb)->flush may still be re-aggregated. This allows already-GRO'd packets with existing frag_list to be re-aggregated into a new GRO session, corrupting the frag_list chain structure. When skb_segment() attempts to unpack these malformed packets, it encounters invalid state and triggers a kernel panic. Scenario (Tethering/Device forwarding): 1. Driver: Generated aggregated packet P1 via LRO with frag_list 2. Dev A: Receives aggregated fraglist packet and flush flag set 3. Dev A: Re-enters GRO, skb_gro_receive_list() is called 4. Missing flush check allows re-aggregation despite flush flag 5. Frag_list chain becomes corrupted (loops or dangling refs) 6. Dev B: TX path calls skb_segment(), crashes on corrupted frag_list Root cause in skb_segment(): The check at line ~4891: if (hsize <= 0 && i >= nfrags && skb_headlen(list_skb) && (skb_headlen(list_skb) == len || sg)) { When frag_list is corrupted by double aggregation, when list_skb is a NULL pointer from skb->next, skb_headlen(list_skb) dereference NULL/corrupted pointers occurs. Call Trace: skb_headlen(NULL skb) skb_segment tcp_gso_segment tcp4_gso_segment inet_gso_segment skb_mac_gso_segment
CVE-2026-68136
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-2026-68136
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": [
{
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"version": "3a1296a38d0cf62bffb9a03c585cbd5dbf15d596",
"lessThan": "7fc7e35212cf58c134310fb47566a844297ceae9",
"versionType": "git"
},
{
"status": "affected",
"version": "3a1296a38d0cf62bffb9a03c585cbd5dbf15d596",
"lessThan": "d1fb23f8f794ac4683127bd49a6422bd87e0ac02",
"versionType": "git"
},
{
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"version": "3a1296a38d0cf62bffb9a03c585cbd5dbf15d596",
"lessThan": "db3e82da616f52e2b27e25e7be3fde2f2a5e54d6",
"versionType": "git"
},
{
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"lessThan": "107e1a469f53a2a70874f3f12bf6fcd23925da1d",
"versionType": "git"
},
{
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"lessThan": "a4dfd46cc8f08a29c6183794790547d0945f3d45",
"versionType": "git"
},
{
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"lessThan": "fc0c0f7a207f0cd2d2aa725696c907f7d03af9e0",
"versionType": "git"
},
{
"status": "affected",
"version": "3a1296a38d0cf62bffb9a03c585cbd5dbf15d596",
"lessThan": "e751256486d0ded20f5a9f9863467f1dce65142f",
"versionType": "git"
}
],
"programFiles": [
"net/core/gro.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.6"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.6",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.266",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/core/gro.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-68136
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #41129 · Revision 1
- Added to Heist Feed
- Publisher date