CVE-2026-74284
- Source
- https://cve.org/CVERecord?id=CVE-2026-74284
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74284.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-74284
- Downstream
BELL (1)
DEBIAN (1)
openSUSE (1)
SUSE (5)
- Related
- Published
- 2026-08-15T05:57:53Z
- Modified
- 2026-10-14T11:27:04Z
- Summary
- net/sched: sch_hfsc: Don't make class passive twice
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_hfsc: Don't make class passive twice
update_vf() is called from two places for the same class during a single dequeue when the class's child qdisc (e.g. codel/fq_codel) drops its last packets while dequeuing:
-
The child calls qdisc_tree_reduce_backlog(), which, now that the child is empty, invokes hfsc_qlen_notify() -> update_vf(cl, 0, 0) and turns the class passive (cl_nactive is decremented up the hierarchy).
-
hfsc_dequeue() then calls update_vf(cl, qdisc_pkt_len(skb), cur_time) to charge the dequeued bytes.
On the second call the class is already passive, but its child qdisc is still empty, so update_vf() arms go_passive again:
if (cl->qdisc->q.qlen == 0 && cl->cl_flags & HFSC_FSC) go_passive = 1;The leaf is then skipped by the cl_nactive == 0 check inside the loop, which does not clear go_passive, so the stale go_passive propagates to the parent and decrements its cl_nactive a second time. A parent that still has other active children is driven to cl_nactive == 0 and removed from the vttree, even though those siblings are still backlogged. They are never dequeued again and the qdisc stalls.
Fix this by only arming go_passive when the class is actually active, so an already-passive class no longer triggers a second passive transition. The byte accounting (cl->cl_total += len) still runs for every ancestor, so dequeued bytes continue to be counted exactly once.
-
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74284.json" }- References
-
- https://git.kernel.org/stable/c/15720cd8fa3fc625146128f89a8e11b0449a20a7
- https://git.kernel.org/stable/c/3a49bbae676fef1ffe548971e6229ae2adeb9d10
- https://git.kernel.org/stable/c/66dbb13eeb2fc339f8f548a9076be4c1a94857b0
- https://git.kernel.org/stable/c/90b662ea25f5e83bb3b8ccec5b93ced810b92fb8
- https://git.kernel.org/stable/c/9221a594c72a1446137926d4c2aa04e345f798dc
- https://git.kernel.org/stable/c/a425c82ff06cda5165e0de3de8c2a445ec1f863e
- https://git.kernel.org/stable/c/b2a017bfcf565721918ec7355a373911d2f2a227
- https://git.kernel.org/stable/c/fc973ecd1a079b9a87c360478542f3a56dea085b
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74284.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-74284
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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
-
Introduced72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7Fixeda425c82ff06cda5165e0de3de8c2a445ec1f863e
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduceda5efc95a33bd4fcb879250852828cc58c7862970Fixedfc973ecd1a079b9a87c360478542f3a56dea085b
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87Fixed15720cd8fa3fc625146128f89a8e11b0449a20a7
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced9030a91235ae4845ec71902c3e0cecfc9ed1f2dfFixedb2a017bfcf565721918ec7355a373911d2f2a227
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedd06476714d2819b550e0cc39222347e2c8941c9dFixed9221a594c72a1446137926d4c2aa04e345f798dc
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced51eb3b65544c9efd6a1026889ee5fb5aa62da3bbFixed66dbb13eeb2fc339f8f548a9076be4c1a94857b0Fixed3a49bbae676fef1ffe548971e6229ae2adeb9d10Fixed90b662ea25f5e83bb3b8ccec5b93ced810b92fb8
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.10.241Fixed5.10.261
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.15.190Fixed5.15.212
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.1.138Fixed6.1.178
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.6.90Fixed6.6.145
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.12.28Fixed6.12.97
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced5.4.297Fixed5.5
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.14.6Fixed6.15
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced9a5fd5c2f4d4afdd5e405083ee53e0789ce76956
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedc1175c4ad01dbc9c979d099861fa90a754f72059
Affected versions
v5.*
v5.10.241
v5.10.242
v5.10.243
v5.10.244
v5.10.245
v5.10.246
v5.10.247
v5.10.248
v5.10.249
v5.10.250
v5.10.251
v5.10.252
v5.10.253
v5.10.254
v5.10.255
v5.10.256
v5.10.257
v5.10.258
v5.10.259
v5.10.260
v5.15.190
v5.15.191
v5.15.192
v5.15.193
v5.15.194
v5.15.195
v5.15.196
v5.15.197
v5.15.198
v5.15.199
v5.15.200
v5.15.201
v5.15.202
v5.15.203
v5.15.204
v5.15.205
v5.15.206
v5.15.207
v5.15.208
v5.15.209
v5.15.210
v5.15.211
v5.4.297
v5.4.298
v5.4.299
v5.4.300
v5.4.301
v5.4.302
v6.*
v6.1.138
v6.1.139
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
v6.1.150
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
v6.1.160
v6.1.161
v6.1.162
v6.1.163
v6.1.164
v6.1.165
v6.1.166
v6.1.167
v6.1.168
v6.1.169
v6.1.170
v6.1.171
v6.1.172
v6.1.173
v6.1.174
v6.1.175
v6.1.176
v6.1.177
v6.12.28
v6.12.29
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
v6.12.40
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
v6.12.50
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
v6.12.60
v6.12.61
v6.12.62
v6.12.63
v6.12.64
v6.12.65
v6.12.66
v6.12.67
v6.12.68
v6.12.69
v6.12.70
v6.12.71
v6.12.72
v6.12.73
v6.12.74
v6.12.75
v6.12.76
v6.12.77
v6.12.78
v6.12.79
v6.12.80
v6.12.81
v6.12.82
v6.12.83
v6.12.84
v6.12.85
v6.12.86
v6.12.87
v6.12.88
v6.12.89
v6.12.90
v6.12.91
v6.12.92
v6.12.93
v6.12.94
v6.12.95
v6.12.96
v6.14.10
v6.14.11
v6.14.6
v6.14.7
v6.14.8
v6.14.9
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
v6.6.110
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
v6.6.120
v6.6.121
v6.6.122
v6.6.123
v6.6.124
v6.6.125
v6.6.126
v6.6.127
v6.6.128
v6.6.129
v6.6.130
v6.6.131
v6.6.132
v6.6.133
v6.6.134
v6.6.135
v6.6.136
v6.6.137
v6.6.138
v6.6.139
v6.6.140
v6.6.141
v6.6.142
v6.6.143
v6.6.144
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
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affectedFixed5.10.261
- Type
- ECOSYSTEM
- Events
-
Introduced5.11.0Fixed5.15.212
- Type
- ECOSYSTEM
- Events
-
Introduced5.16.0Fixed6.1.178
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.6.145
- Type
- ECOSYSTEM
- Events
-
Introduced6.7.0Fixed6.12.97
- Type
- ECOSYSTEM
- Events
-
Introduced6.13.0Fixed6.18.40
- Type
- ECOSYSTEM
- Events
-
Introduced6.15.0Fixed7.1.5