CVE-2026-99074
- Source
- https://cve.org/CVERecord?id=CVE-2026-99074
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-99074.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2026-99074
- Downstream
- Published
- 2026-10-23T12:23:17Z
- Modified
- 2026-11-13T04:07:33Z
- Summary
- ipv4: stop PMTU walk when nexthop group shrinks
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
ipv4: stop PMTU walk when nexthop group shrinks
Commit 7d3f3b4367f3 ("net: ipv4: Cache pmtu for all packet paths if multipath enabled") made __ip_rt_update_pmtu() update every path.
For nexthop objects, fib_info_num_path() and fib_info_nhc() independently load nh->nh_grp. RCU protects each group's lifetime but does not make the loads observe the same group. If replacement shrinks the group after the loop accepts an index, fib_info_nhc() returns NULL and update_or_create_fnhe() dereferences it.
A deterministic probe only widened the existing window between the real operations. On v7.2, an RTM_NEWNEXTHOP replacement published a one-member group after the PMTU reader accepted index 1 from a two-member group, producing:
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: update_or_create_fnhe+0x45/0x15b0
Stop when the indexed path is absent. Groups are dense, so no later index exists in that snapshot. The same real-writer window completed 114,423 PMTU iterations without an oops with this check. A reproducer is available on request.
Replacement requires CAP_NET_ADMIN in the network namespace. Where unprivileged user namespaces are permitted, a local user can obtain it in a new user and network namespace.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99074.json" }- References
-
- https://git.kernel.org/stable/c/6619e01855e65ef35723685a557e3eb106f4ecf5
- https://git.kernel.org/stable/c/7fd60d3c9a1e1b11ef5f1643bbae78d91eae2f4a
- https://git.kernel.org/stable/c/82d83eec893d8ae84f280aec44c60d9fdecc62b5
- https://git.kernel.org/stable/c/a411df69524f91fe3adb8f9544d33e701fc9732c
- https://git.kernel.org/stable/c/c60d17d6dd61adc761ac6f65a008fefbc54cbf87
- https://git.kernel.org/stable/c/c6d670ac656badfd0e15355e07a13a6bdf3b69fd
- https://git.kernel.org/stable/c/f27483f9975b5065ff67054cc7eb8edac6083488
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/99xxx/CVE-2026-99074.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-99074
- 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
-
Introducedfc07a232326a623d0be482e307c08ea7049c2846Fixed82d83eec893d8ae84f280aec44c60d9fdecc62b5
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedb1f7bdee5750d6cbb9497140cd6582abc5fdcb9eFixeda411df69524f91fe3adb8f9544d33e701fc9732c
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced3bed2abab4a682d426624ce9add9d7b6d475d4e4Fixed7fd60d3c9a1e1b11ef5f1643bbae78d91eae2f4a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced7f5005457b3072fe1ddf15bfef869f2a1d98e05eFixedc60d17d6dd61adc761ac6f65a008fefbc54cbf87
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced7d3f3b4367f315a61fc615e3138f3d320da8c466Fixedc6d670ac656badfd0e15355e07a13a6bdf3b69fdFixedf27483f9975b5065ff67054cc7eb8edac6083488Fixed6619e01855e65ef35723685a557e3eb106f4ecf5
Affected versions
v5.*
v5.15.179
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
v5.15.190
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
v5.15.212
v5.15.213
v5.15.214
v5.15.215
v5.15.216
v5.15.217
v5.15.218
v5.15.219
v5.15.220
v5.15.221
v5.15.222
v5.15.223
v6.*
v6.1.129
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
v6.1.140
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
v6.1.178
v6.1.179
v6.1.180
v6.1.181
v6.1.182
v6.1.183
v6.1.184
v6.1.185
v6.1.186
v6.1.187
v6.1.188
v6.1.189
v6.1.190
v6.12.100
v6.12.101
v6.12.102
v6.12.103
v6.12.104
v6.12.105
v6.12.106
v6.12.107
v6.12.108
v6.12.109
v6.12.110
v6.12.111
v6.12.112
v6.12.16
v6.12.17
v6.12.18
v6.12.19
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
v6.12.30
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
v6.12.97
v6.12.98
v6.12.99
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
v6.6.145
v6.6.146
v6.6.147
v6.6.148
v6.6.149
v6.6.150
v6.6.151
v6.6.152
v6.6.153
v6.6.154
v6.6.155
v6.6.156
v6.6.157
v6.6.158
v6.6.159
v6.6.79
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
v6.6.90
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
-
Introduced5.15.179Fixed5.15.224
- Type
- ECOSYSTEM
- Events
-
Introduced6.1.129Fixed6.1.191
- Type
- ECOSYSTEM
- Events
-
Introduced6.6.79Fixed6.6.160
- Type
- ECOSYSTEM
- Events
-
Introduced6.12.16Fixed6.12.113
- Type
- ECOSYSTEM
- Events
-
Introduced6.13.0Fixed6.18.57
- Type
- ECOSYSTEM
- Events
-
Introduced6.19.0Fixed7.2.11