{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.176-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.94-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.10-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "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-\u003ezone };                 struct tcf_ct_flow_table *ct_ft;                 int err = -ENOMEM;                  mutex_lock(\u0026zones_mutex);                 ct_ft = rhashtable_lookup_fast(\u0026zones_ht, \u0026key, zones_params); // [1]                 if (ct_ft \u0026\u0026 refcount_inc_not_zero(\u0026ct_ft-\u003eref)) // [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 object from being freed. However, at the point of function return, rcu_read_unlock() has already been called, and there is nothing preventing ct_ft from being freed before reaching refcount_inc_not_zero(\u0026ct_ft-\u003eref) at [2]. This interval becomes the race window, during which ct_ft can be freed.  Free Process:  tcf_ct_flow_table_put() is executed through the path tcf_ct_cleanup() call_rcu() tcf_ct_params_free_rcu() tcf_ct_params_free() tcf_ct_flow_table_put().  static void tcf_ct_flow_table_put(struct tcf_ct_flow_table *ct_ft) {                 if (refcount_dec_and_test(\u0026ct_ft-\u003eref)) {                                 rhashtable_remove_fast(\u0026zones_ht, \u0026ct_ft-\u003enode, zones_params);                                 INIT_RCU_WORK(\u0026ct_ft-\u003erwork, tcf_ct_flow_table_cleanup_work); // [3]                                 queue_rcu_work(act_ct_wq, \u0026ct_ft-\u003erwork);                 } }  At [3], tcf_ct_flow_table_cleanup_work() is scheduled as RCU work  static void tcf_ct_flow_table_cleanup_work(struct work_struct *work)  {                 struct tcf_ct_flow_table *ct_ft;                 struct flow_block *block;                  ct_ft = container_of(to_rcu_work(work), struct tcf_ct_flow_table,                                                                 rwork);                 nf_flow_table_free(\u0026ct_ft-\u003enf_ft);                 block = \u0026ct_ft-\u003enf_ft.flow_block;                 down_write(\u0026ct_ft-\u003enf_ft.flow_block_lock);                 WARN_ON(!list_empty(\u0026block-\u003ecb_list));                 up_write(\u0026ct_ft-\u003enf_ft.flow_block_lock);                 kfree(ct_ft); // [4]                  module_put(THIS_MODULE); }  tcf_ct_flow_table_cleanup_work() frees ct_ft at [4]. When this function executes between [1] and [2], UAF occurs.  This race condition has a very short race window, making it generally difficult to trigger. Therefore, to trigger the vulnerability an msleep(100) was inserted after[1]",
  "id": "DEBIAN-CVE-2026-46319",
  "modified": "2026-09-14T16:47:40.851398288Z",
  "published": "2026-06-09T13:16:37.210Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-46319"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-46319"
  ]
}