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net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: don't WARN on benign flow_offload_alloc() failure flow_offload_alloc() returns NULL when the conntrack entry is dying (e.g. raced with a conntrack flush) or when the GFP_ATOMIC allocation fails; both are expected under load and neither is a kernel bug. This path runs from softirq on every committed packet, so with panic_on_warn=1 an unprivileged user can panic the box just by racing a conntrack flush against a `tc ... action ct commit` classifier. Reproduced with a custom repro under QEMU: a small, fixed set of UDP flows through `tc filter ... action ct commit` on lo, raced against threads flooding bare ctnetlink CT_DELETE (flush) requests. Hits WARNING: net/sched/act_ct.c:437 (tcf_ct_flow_table_add(), inlined into tcf_ct_act() in this build) within ~15s on the unpatched kernel; same setup is clean on the patched kernel. The fix itself is behavior-preserving: both branches already did `goto err_alloc` before and after, only the WARN is removed.

Announced Source revision 1
Original source ↗

CVE-2026-98622

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-2026-98622

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": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "e8fcf3f08834e939b797311742ee72b1e2a08096",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "af475f599270e59313552e6c6f3af8507da672b8",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "424ba52c0058deeb940d02cba52eb0aeb288db33",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "d512c484bd93a5f2794aa03c9faeb7bcb82dbd4a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "d805560ad69cb266d669341ca01e26bffb0d2c67",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "00734f3684fcec42c319bedfe68a5d357c720b53",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "650787233c2fd6e515a7c5f371019a9fa080ccd2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "64ff70b80fd403110b67dd9f7184a604fdb0da43",
        "lessThan": "47abe7a5c4eb53269aca3506446f851572a059a3",
        "versionType": "git"
      }
    ],
    "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": "5.7"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.7",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.271",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.55",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/act_ct.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98622

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38642 · Revision 1
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Publisher date
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