net/sched: act_ct: fix sk_buff leak when the header checks reject a packet
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: fix sk_buff leak when the header checks reject a packet tcf_ct_handle_fragments() runs its header sanity checks before handing anything to the defragmentation engine: if (family == NFPROTO_IPV4) err = tcf_ct_ipv4_is_fragment(skb, &frag); else err = tcf_ct_ipv6_is_fragment(skb, &frag); if (err || !frag) return err; tcf_ct_ipv4_is_fragment() returns -EINVAL or -ENOMEM; tcf_ct_ipv6_is_fragment() adds -EPROTO when ipv6_find_hdr() fails. None of them frees or queues the skb, so on that path the caller still owns it. tcf_ct_act() however funnels every non-zero return into the ownership-transfer exit: err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag); if (err) goto out_frag; ... out_frag: if (err != -EINPROGRESS) tcf_action_inc_drop_qstats(&c->common); return TC_ACT_CONSUMED; TC_ACT_CONSUMED means the action took ownership of the skb, so no caller frees it - sch_handle_ingress(), sch_handle_egress() and tcf_qevent_handle() all deliberately skip the free for that verdict. The skb is therefore orphaned: one sk_buff plus its data buffer is leaked per malformed packet, unbounded. Note the drop counter is already incremented for these errors, so the statistics claim a drop that never happens. Three different ownership states reach out_frag: today - the skb may be queued by the defrag engine (-EINPROGRESS), already freed by nf_ct_handle_fragments(), or still owned by us. Tell the caller
CVE-2026-74621
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-2026-74621
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": "172ba7d46c202e679f3ccb10264c67416aaeb1c4",
"lessThan": "b5dbecc2016e1692fd1c2532af9c41ba729cb747",
"versionType": "git"
},
{
"status": "affected",
"version": "0b5b831122fc3789fff75be433ba3e4dd7b779d4",
"lessThan": "23e97d594ddd0153020c506d5041048fbde1beb4",
"versionType": "git"
},
{
"status": "affected",
"version": "73f7da5fd124f2cda9161e2e46114915e6e82e97",
"lessThan": "737873a59905a54ca0d2d127ef882f3f88bf4379",
"versionType": "git"
},
{
"status": "affected",
"version": "3f14b377d01d8357eba032b4cabc8c1149b458b6",
"lessThan": "47d99828591d0fe8be4b9c8992ff3b8e47968db9",
"versionType": "git"
},
{
"status": "affected",
"version": "3f14b377d01d8357eba032b4cabc8c1149b458b6",
"lessThan": "b47bb899e04b5407c5a63fe88d4b6676586a6e84",
"versionType": "git"
},
{
"status": "affected",
"version": "3f14b377d01d8357eba032b4cabc8c1149b458b6",
"lessThan": "439d3e404f9d5e515911cc8132cde198b337c19e",
"versionType": "git"
},
{
"status": "affected",
"version": "3f14b377d01d8357eba032b4cabc8c1149b458b6",
"lessThan": "8a7ed561671aa6a911a2de99e59ef670a4d0b1df",
"versionType": "git"
},
{
"status": "affected",
"version": "f5346df0591d10bc948761ca854b1fae6d2ef441",
"versionType": "git"
},
{
"status": "affected",
"version": "5.15.148",
"lessThan": "5.15.217",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.75",
"lessThan": "6.1.184",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.14",
"lessThan": "6.6.152",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.7.2",
"lessThan": "6.8",
"versionType": "semver"
}
],
"programFiles": [
"net/sched/act_ct.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.217",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/act_ct.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74621
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33244 · Revision 1
- Added to Heist Feed
- Publisher date