CVE-2026-89555

Source
https://cve.org/CVERecord?id=CVE-2026-89555
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89555.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-89555
Downstream
AZL (1)
BELL (1)
CLSA (9)
DEBIAN (1)
MGASA (2)
OESA (1)
openSUSE (1)
UBUNTU (1)
Related
Published
2026-09-11T19:44:28Z
Modified
2026-10-24T02:30:40Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
mpls: reload header after pskb_may_pull()
Details

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

mpls: reload header after pskb_may_pull()

mpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop when an MPLS route has multiple nexthops. While walking the MPLS label stack, the hash routine caches hdr for the current label. After finding the bottom-of-stack label, it calls pskb_may_pull() before reading the inner IP header.

If an skb is constructed with the inner IP header in nonlinear data and insufficient tailroom in the linear head, pskb_may_pull() calls pskb_expand_head() to replace the skb head and free the old one. This leaves hdr pointing to freed memory. The IPv6 path can invalidate hdr again when it performs a second pull for the larger header.

The issue was found through static analysis. A reproducer sending a legal Geneve packet through a bareudp/MPLS multipath setup triggered the same KASAN report in 2 of 2 unpatched runs:

BUG: KASAN: slab-use-after-free in mpls_select_multipath Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23

Call Trace: mpls_select_multipath mpls_forward __netif_receive_skb_list_core netif_receive_skb_list_internal napi_complete_done gro_cell_poll __napi_poll net_rx_action

Freed by task 23: kfree pskb_expand_head __pskb_pull_tail mpls_select_multipath

Reload hdr from the current skb head after each successful pull before deriving the inner IPv4 or IPv6 header pointer.

Database specific
{
    "cna_assigner":  "Linux",
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89555.json"
}
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
9f427a0e474a67b454420c131709600d44850486
Fixed
aa4fe0b450a461aa1162fe8375f5d28f4c957df8
Fixed
b1c0783b2facc398437ad8f8b86c636d7a78f8db
Fixed
bfaaff99238326166694354a63a76c02563f98b1
Fixed
d9640239827d6d0cb84263b590f7a4f1596c17eb
Fixed
fed638a248116b8a249bd4202d28e5934bdc65ad
Fixed
d82b90a38c2ca8a0694428eab0e9551c23f2447d
Fixed
49d38c1b4390412f8950d33dfaee0ccbd17beb81
Fixed
29e63b8d9fc150cc191b1c6eb7e16e1247e1b650
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4.9.8
Fixed
4.10
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb

Affected versions

v4.*
v4.9.10
v4.9.100
v4.9.101
v4.9.102
v4.9.103
v4.9.104
v4.9.105
v4.9.106
v4.9.107
v4.9.108
v4.9.109
v4.9.11
v4.9.110
v4.9.111
v4.9.112
v4.9.113
v4.9.114
v4.9.115
v4.9.116
v4.9.117
v4.9.118
v4.9.119
v4.9.12
v4.9.120
v4.9.121
v4.9.122
v4.9.123
v4.9.124
v4.9.125
v4.9.126
v4.9.127
v4.9.128
v4.9.129
v4.9.13
v4.9.130
v4.9.131
v4.9.132
v4.9.133
v4.9.134
v4.9.135
v4.9.136
v4.9.137
v4.9.138
v4.9.139
v4.9.14
v4.9.140
v4.9.141
v4.9.142
v4.9.143
v4.9.144
v4.9.145
v4.9.146
v4.9.147
v4.9.148
v4.9.149
v4.9.15
v4.9.150
v4.9.151
v4.9.152
v4.9.153
v4.9.154
v4.9.155
v4.9.156
v4.9.157
v4.9.158
v4.9.159
v4.9.16
v4.9.160
v4.9.161
v4.9.162
v4.9.163
v4.9.164
v4.9.165
v4.9.166
v4.9.167
v4.9.168
v4.9.169
v4.9.17
v4.9.170
v4.9.171
v4.9.172
v4.9.173
v4.9.174
v4.9.175
v4.9.176
v4.9.177
v4.9.178
v4.9.179
v4.9.18
v4.9.180
v4.9.181
v4.9.182
v4.9.183
v4.9.184
v4.9.185
v4.9.186
v4.9.187
v4.9.188
v4.9.189
v4.9.19
v4.9.190
v4.9.191
v4.9.192
v4.9.193
v4.9.194
v4.9.195
v4.9.196
v4.9.197
v4.9.198
v4.9.199
v4.9.20
v4.9.200
v4.9.201
v4.9.202
v4.9.203
v4.9.204
v4.9.205
v4.9.206
v4.9.207
v4.9.208
v4.9.209
v4.9.21
v4.9.210
v4.9.211
v4.9.212
v4.9.213
v4.9.214
v4.9.215
v4.9.216
v4.9.217
v4.9.218
v4.9.219
v4.9.22
v4.9.220
v4.9.221
v4.9.222
v4.9.223
v4.9.224
v4.9.225
v4.9.226
v4.9.227
v4.9.228
v4.9.229
v4.9.23
v4.9.230
v4.9.231
v4.9.232
v4.9.233
v4.9.234
v4.9.235
v4.9.236
v4.9.237
v4.9.238
v4.9.239
v4.9.24
v4.9.240
v4.9.241
v4.9.242
v4.9.243
v4.9.244
v4.9.245
v4.9.246
v4.9.247
v4.9.248
v4.9.249
v4.9.25
v4.9.250
v4.9.251
v4.9.252
v4.9.253
v4.9.254
v4.9.255
v4.9.256
v4.9.257
v4.9.258
v4.9.259
v4.9.26
v4.9.260
v4.9.261
v4.9.262
v4.9.263
v4.9.264
v4.9.265
v4.9.266
v4.9.267
v4.9.268
v4.9.269
v4.9.27
v4.9.270
v4.9.271
v4.9.272
v4.9.273
v4.9.274
v4.9.275
v4.9.276
v4.9.277
v4.9.278
v4.9.279
v4.9.28
v4.9.280
v4.9.281
v4.9.282
v4.9.283
v4.9.284
v4.9.285
v4.9.286
v4.9.287
v4.9.288
v4.9.289
v4.9.29
v4.9.290
v4.9.291
v4.9.292
v4.9.293
v4.9.294
v4.9.295
v4.9.296
v4.9.297
v4.9.298
v4.9.299
v4.9.30
v4.9.300
v4.9.301
v4.9.302
v4.9.303
v4.9.304
v4.9.305
v4.9.306
v4.9.307
v4.9.308
v4.9.309
v4.9.31
v4.9.310
v4.9.311
v4.9.312
v4.9.313
v4.9.314
v4.9.315
v4.9.316
v4.9.317
v4.9.318
v4.9.319
v4.9.32
v4.9.320
v4.9.321
v4.9.322
v4.9.323
v4.9.324
v4.9.325
v4.9.326
v4.9.327
v4.9.328
v4.9.329
v4.9.33
v4.9.330
v4.9.331
v4.9.332
v4.9.333
v4.9.334
v4.9.335
v4.9.336
v4.9.337
v4.9.34
v4.9.35
v4.9.36
v4.9.37
v4.9.38
v4.9.39
v4.9.40
v4.9.41
v4.9.42
v4.9.43
v4.9.44
v4.9.45
v4.9.46
v4.9.47
v4.9.48
v4.9.49
v4.9.50
v4.9.51
v4.9.52
v4.9.53
v4.9.54
v4.9.55
v4.9.56
v4.9.57
v4.9.58
v4.9.59
v4.9.60
v4.9.61
v4.9.62
v4.9.63
v4.9.64
v4.9.65
v4.9.66
v4.9.67
v4.9.68
v4.9.69
v4.9.70
v4.9.71
v4.9.72
v4.9.73
v4.9.74
v4.9.75
v4.9.76
v4.9.77
v4.9.78
v4.9.79
v4.9.8
v4.9.80
v4.9.81
v4.9.82
v4.9.83
v4.9.84
v4.9.85
v4.9.86
v4.9.87
v4.9.88
v4.9.89
v4.9.9
v4.9.90
v4.9.91
v4.9.92
v4.9.93
v4.9.94
v4.9.95
v4.9.96
v4.9.97
v4.9.98
v4.9.99

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89555.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
4.10.0
Fixed
5.10.270
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.221
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.188
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.157
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.109
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.18.50
Type
ECOSYSTEM
Events
Introduced
6.19.0
Fixed
7.2.4

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89555.json"