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net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload There is a TOCTOU race condition in flower lockless approach between sizing a flow_rule buffer and filling it. zdi-disclosures@trendmicro.com reports: The cls_flower classifier operates with TCF_PROTO_OPS_DOIT_UNLOCKED (fl_change runs without RTNL), while RTM_NEWACTION holds RTNL, so the independent locking domains make the race reachable in practice. KASAN confirms: BUG: KASAN: slab-out-of-bounds in tcf_pedit_offload_act_setup+0x81b/0x930 Write of size 4 at addr ffff888001f27520 by task poc-toctou/312 The buggy address is located 0 bytes to the right of allocated 288-byte region [ffff888001f27400, ffff888001f27520) (cache kmalloc-512) Note: The result is a heap OOB write attacker-controlled content into the adjacent slab object (requires CAP_NET_ADMIN). The fix introduces reading tcfp_nkeys under act->tcfa_lock in all places using a new tcf_pedit_nkeys_locked() which replaces the old tcf_pedit_nkeys(). Additionally we close the remaining TOCTOU window between the sizing read and the fill reads by more careful accounting. Rather than silently truncating the key count, which leads to incorrect action semantics offloaded to hardware and secondary OOB writes if the remaining capacity is zero or consumed by prior actions, we enforce remaining capacity checks and return -ENOSPC if the required space exceeds the remaining capacity.

Announced Source revision 1
Original source ↗

CVE-2026-72338

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-2026-72338

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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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": "71d0ed7079dffbc5cd0941d77d9b84e04109c9bb",
        "lessThan": "0d8532a5e972a5351cf4ee4a435e0d65cbba8f23",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "71d0ed7079dffbc5cd0941d77d9b84e04109c9bb",
        "lessThan": "27488e1a7f19757e6146edca9458ed4ffc545557",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "71d0ed7079dffbc5cd0941d77d9b84e04109c9bb",
        "lessThan": "6f9b23eb92a894ae1118893996943990ee0b860e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "71d0ed7079dffbc5cd0941d77d9b84e04109c9bb",
        "lessThan": "8e49cd891bda447c68122d672510a604a8bb6b24",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "71d0ed7079dffbc5cd0941d77d9b84e04109c9bb",
        "lessThan": "8b519cbcabe836a441369fbec1a8a6518a709251",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "include/net/tc_act/tc_pedit.h",
      "net/sched/act_api.c",
      "net/sched/act_pedit.c",
      "net/sched/cls_api.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.11"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.11",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/tc_act/tc_pedit.h",
      "net/sched/act_api.c",
      "net/sched/act_pedit.c",
      "net/sched/cls_api.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72338

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#33028 · Revision 1
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Publisher date
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