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net/sched: act_ct: Only release RCU read lock after ct_ft

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_ct: Only release RCU read lock after ct_ft When looking up a flow table in act_ct in tcf_ct_flow_table_get(), rhashtable_lookup_fast() internally opens and closes an RCU read critical section before returning ct_ft. The tcf_ct_flow_table_cleanup_work() can complete before refcount_inc_not_zero() is invoked on the returned ct_ft resulting in a UAF on the already freed ct_ft object. This vulnerability can lead to privilege escalation. Analysis from zdi-disclosures@trendmicro.com: When initializing act_ct, tcf_ct_init() is called, which internally triggers tcf_ct_flow_table_get(). static int tcf_ct_flow_table_get(struct net *net, struct tcf_ct_params *params) { struct zones_ht_key key = { .net = net, .zone = params->zone }; struct tcf_ct_flow_table *ct_ft; int err = -ENOMEM; mutex_lock(&zones_mutex); ct_ft = rhashtable_lookup_fast(&zones_ht, &key, zones_params); // [1] if (ct_ft && refcount_inc_not_zero(&ct_ft->ref)) // [2] goto out_unlock; ... } static __always_inline void *rhashtable_lookup_fast( struct rhashtable *ht, const void *key, const struct rhashtable_params params) { void *obj; rcu_read_lock(); obj = rhashtable_lookup(ht, key, params); rcu_read_unlock(); return obj; } At [1], rhashtable_lookup_fast() looks up and returns the corresponding ct_ft from zones_ht . The lookup is performed within an RCU read critical section through rcu_read_lock() / rcu_read_unlock(), which prevents the obje

Announced Source revision 1
Original source ↗

CVE-2026-46319

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-2026-46319

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": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "ece578ca61e572df96cfc80456357ebfae0b4b9e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "a2e0c045c87aa252eb61412e67dd91f2c2b19f81",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "67c9ecc9f2575273ed1323e312881fc98ac83d6d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "f23424a0ddadb494d4bd57056a7ca703312d3a7b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "17dfb67cb399b660105d9a8c6100851c0d0cdc70",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "4c727c6967a41b37efe0f26332ca9ec5b74785a3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "3e20e1b3058e0b94638e7b931c138e840e266724",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "138470a9b2cc2e26e6018300394afc3858a54e6a",
        "lessThan": "f462dca0c8415bf0058d0ffa476354c4476d0f09",
        "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": "5.10.258",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.209",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.175",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.141",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.91",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.33",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/act_ct.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-46319

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#40679 · Revision 1
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Publisher date
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