CVE-2026-80808

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Source
https://cve.org/CVERecord?id=CVE-2026-80808
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80808.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-80808
Downstream
Related
Published
2026-09-04T15:13:28Z
Modified
2026-10-08T02:52:03Z
Summary
ext4: stop retrying saturated xattr cache entries
Details

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

ext4: stop retrying saturated xattr cache entries

ext4_xattr_block_set() retries when a cache entry selected for reuse has a saturated reference count after taking the buffer lock. The retry returns to the mbcache lookup without making that entry ineligible, so it can select the same unusable entry indefinitely. A task spinning there can hold the parent directory's i_rwsem and leave concurrent rmdir callers blocked.

Normally a reusable entry has a reference count below EXT4_XATTR_REFCOUNT_MAX because the count and MBE_REUSABLE_B are updated under the same buffer lock. A corrupted filesystem can violate that invariant. The syzbot reproducer reports allocator and xattr corruption before triggering this retry loop.

Check the untrusted on-disk count before incrementing it, avoiding overflow, and clear MBE_REUSABLE_B when it is already saturated. The next lookup then skips the entry that was just proven unusable. This mirrors the normal transition at EXT4_XATTR_REFCOUNT_MAX; the release path marks the entry reusable again on the exact 1024-to-1023 transition.

Using the same QEMU harness and guest parameters, current unpatched Linux hung in 6 of 8 420-second trials with the do_rmdir signature; representative NMI backtraces caught the owner spinning in ext4_xattr_block_set(). The patched kernel completed 28 of 28 trials without a hung-task report; the final twelve trials exercised the reviewed overflow-safe form of the change. syzbot's patch testing also completed without reproducing the hang.

Database specific 
{
    "cna_assigner":  "Linux",
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80808.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
1a56cd972ce121b6cf2517a47a578782bbd2ec95
Fixed
119a2f053242ed75bdd2ebc95baf3ae7db6ccacf
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
1be97463696c7291a3e1547614e96432b0bd3add
Fixed
61631352a5b405c89be579de00903b72e6888aa4
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
65f8b80053a1b2fd602daa6814e62d6fa90e5e9b
Fixed
8865cd664484517703df5c18a965dc3227572b87
Fixed
a40c45268f4358207aa9c53764fed2e05f62986a
Fixed
889ec86464d261f026f6c334040cfc6c58c99d58
Fixed
4902a5cba21aeaf91e6b29e20e0967a5f6abdcd9
Fixed
55ee6533c1db7f7656fa8dd19637f3f8b8c08dc5
Fixed
dbd4aea175ad3c46436acb251e817b4374628072
Fixed
54b6bd40898de7906acb2bccc9a96d1b8e6b4323
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5.10.163
Fixed
5.10.267
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5.15.61
Fixed
5.15.218
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
4.19.270
Fixed
4.20
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5.4.229
Fixed
5.5
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5.18.18
Fixed
5.19
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
5.19.2
Fixed
5.20
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
98953044b3cdb2cb7d82e7365b659e2ed4f4ca4d
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
af8ecc8d20e72130771cc076bce7fcf17ccda6c4
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
c6fac5cf5a5098732623bcd00a8a3eb9f5465144
Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
96fa141fa295ae9428da73c56c9852053b575c04

Affected versions

v4.*
v4.19.270
v4.19.271
v4.19.272
v4.19.273
v4.19.274
v4.19.275
v4.19.276
v4.19.277
v4.19.278
v4.19.279
v4.19.280
v4.19.281
v4.19.282
v4.19.283
v4.19.284
v4.19.285
v4.19.286
v4.19.287
v4.19.288
v4.19.289
v4.19.290
v4.19.291
v4.19.292
v4.19.293
v4.19.294
v4.19.295
v4.19.296
v4.19.297
v4.19.298
v4.19.299
v4.19.300
v4.19.301
v4.19.302
v4.19.303
v4.19.304
v4.19.305
v4.19.306
v4.19.307
v4.19.308
v4.19.309
v4.19.310
v4.19.311
v4.19.312
v4.19.313
v4.19.314
v4.19.315
v4.19.316
v4.19.317
v4.19.318
v4.19.319
v4.19.320
v4.19.321
v4.19.322
v4.19.323
v4.19.324
v4.19.325
v5.*
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
v5.10.248
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
v5.10.261
v5.10.262
v5.10.263
v5.10.264
v5.10.265
v5.10.266
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
v5.15.110
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
v5.15.120
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
v5.15.130
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
v5.15.140
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
v5.15.150
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
v5.15.160
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
v5.15.170
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
v5.15.180
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
v5.15.61
v5.15.62
v5.15.63
v5.15.64
v5.15.65
v5.15.66
v5.15.67
v5.15.68
v5.15.69
v5.15.70
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
v5.15.80
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
v5.15.90
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
v5.18.18
v5.18.19
v5.19.10
v5.19.11
v5.19.12
v5.19.13
v5.19.14
v5.19.15
v5.19.16
v5.19.17
v5.19.2
v5.19.3
v5.19.4
v5.19.5
v5.19.6
v5.19.7
v5.19.8
v5.19.9
v5.4.229
v5.4.230
v5.4.231
v5.4.232
v5.4.233
v5.4.234
v5.4.235
v5.4.236
v5.4.237
v5.4.238
v5.4.239
v5.4.240
v5.4.241
v5.4.242
v5.4.243
v5.4.244
v5.4.245
v5.4.246
v5.4.247
v5.4.248
v5.4.249
v5.4.250
v5.4.251
v5.4.252
v5.4.253
v5.4.254
v5.4.255
v5.4.256
v5.4.257
v5.4.258
v5.4.259
v5.4.260
v5.4.261
v5.4.262
v5.4.263
v5.4.264
v5.4.265
v5.4.266
v5.4.267
v5.4.268
v5.4.269
v5.4.270
v5.4.271
v5.4.272
v5.4.273
v5.4.274
v5.4.275
v5.4.276
v5.4.277
v5.4.278
v5.4.279
v5.4.280
v5.4.281
v5.4.282
v5.4.283
v5.4.284
v5.4.285
v5.4.286
v5.4.287
v5.4.288
v5.4.289
v5.4.290
v5.4.291
v5.4.292
v5.4.293
v5.4.294
v5.4.295
v5.4.296
v5.4.297
v5.4.298
v5.4.299
v5.4.300
v5.4.301
v5.4.302

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80808.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
5.10.267
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.218
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.185
Type
ECOSYSTEM
Events
Introduced
6.0.0
Fixed
6.6.154
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.12.106
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.18.47
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
7.1.11
Type
ECOSYSTEM
Events
Introduced
6.19.0
Fixed
7.2.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80808.json"