FKIE_CVE-2026-31551
Vulnerability from fkie_nvd - Published: 2026-04-24 15:16 - Updated: 2026-06-17 10:33
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.
syzbot reported static_branch_dec() underflow in aql_enable_write(). [0]
The problem is that aql_enable_write() does not serialise concurrent
write()s to the debugfs.
aql_enable_write() checks static_key_false(&aql_disable.key) and
later calls static_branch_inc() or static_branch_dec(), but the
state may change between the two calls.
aql_disable does not need to track inc/dec.
Let's use static_branch_enable() and static_branch_disable().
[0]:
val == 0
WARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288
Modules linked in:
CPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311
Code: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 <0f> 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00
RSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4
RDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a
R13: 1ffff9200173ef88 R14: 0000000000000001 R15: ffffc9000b9f7e98
FS: 00007f530dd726c0(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001140 CR3: 000000007cc4a000 CR4: 00000000003526f0
Call Trace:
<TASK>
__static_key_slow_dec_cpuslocked kernel/jump_label.c:297 [inline]
__static_key_slow_dec kernel/jump_label.c:321 [inline]
static_key_slow_dec+0x7c/0xc0 kernel/jump_label.c:336
aql_enable_write+0x2b2/0x310 net/mac80211/debugfs.c:343
short_proxy_write+0x133/0x1a0 fs/debugfs/file.c:383
vfs_write+0x2aa/0x1070 fs/read_write.c:684
ksys_pwrite64 fs/read_write.c:793 [inline]
__do_sys_pwrite64 fs/read_write.c:801 [inline]
__se_sys_pwrite64 fs/read_write.c:798 [inline]
__x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:798
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f530cf9aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f530dd72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f530d215fa0 RCX: 00007f530cf9aeb9
RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000010
RBP: 00007f530d008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 4200000000000005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f530d216038 R14: 00007f530d215fa0 R15: 00007ffde89fb978
</TASK>
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 5.12 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 | |
| linux | linux_kernel | 7.0 |
{
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{
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"programFiles": [
"net/mac80211/debugfs.c"
],
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"vendor": "Linux",
"versions": [
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"versionType": "git"
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{
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"version": "e908435e402aff23c9b0b3c59c7cd12b08b681b0",
"versionType": "git"
},
{
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"status": "affected",
"version": "e908435e402aff23c9b0b3c59c7cd12b08b681b0",
"versionType": "git"
},
{
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"versionType": "git"
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"status": "affected",
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"versionType": "git"
},
{
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"version": "e908435e402aff23c9b0b3c59c7cd12b08b681b0",
"versionType": "git"
}
]
},
{
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"product": "Linux",
"programFiles": [
"net/mac80211/debugfs.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.12"
},
{
"lessThan": "5.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.20",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.10",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"configurations": [
{
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"versionEndExcluding": "5.15.203",
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},
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"negate": false,
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: Fix static_branch_dec() underflow for aql_disable.\n\nsyzbot reported static_branch_dec() underflow in aql_enable_write(). [0]\n\nThe problem is that aql_enable_write() does not serialise concurrent\nwrite()s to the debugfs.\n\naql_enable_write() checks static_key_false(\u0026aql_disable.key) and\nlater calls static_branch_inc() or static_branch_dec(), but the\nstate may change between the two calls.\n\naql_disable does not need to track inc/dec.\n\nLet\u0027s use static_branch_enable() and static_branch_disable().\n\n[0]:\nval == 0\nWARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288\nModules linked in:\nCPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G U L syzkaller #0 PREEMPT(full)\nTainted: [U]=USER, [L]=SOFTLOCKUP\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026\nRIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311\nCode: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 \u003c0f\u003e 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00\nRSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4\nRDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000\nRBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000a\nR13: 1ffff9200173ef88 R14: 0000000000000001 R15: ffffc9000b9f7e98\nFS: 00007f530dd726c0(0000) GS:ffff8881245e3000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000200000001140 CR3: 000000007cc4a000 CR4: 00000000003526f0\nCall Trace:\n \u003cTASK\u003e\n __static_key_slow_dec_cpuslocked kernel/jump_label.c:297 [inline]\n __static_key_slow_dec kernel/jump_label.c:321 [inline]\n static_key_slow_dec+0x7c/0xc0 kernel/jump_label.c:336\n aql_enable_write+0x2b2/0x310 net/mac80211/debugfs.c:343\n short_proxy_write+0x133/0x1a0 fs/debugfs/file.c:383\n vfs_write+0x2aa/0x1070 fs/read_write.c:684\n ksys_pwrite64 fs/read_write.c:793 [inline]\n __do_sys_pwrite64 fs/read_write.c:801 [inline]\n __se_sys_pwrite64 fs/read_write.c:798 [inline]\n __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:798\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f530cf9aeb9\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007f530dd72028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012\nRAX: ffffffffffffffda RBX: 00007f530d215fa0 RCX: 00007f530cf9aeb9\nRDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000010\nRBP: 00007f530d008c1f R08: 0000000000000000 R09: 0000000000000000\nR10: 4200000000000005 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007f530d216038 R14: 00007f530d215fa0 R15: 00007ffde89fb978\n \u003c/TASK\u003e"
}
],
"id": "CVE-2026-31551",
"lastModified": "2026-06-17T10:33:57.690",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2026-04-24T15:16:29.350",
"references": [
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
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],
"url": "https://git.kernel.org/stable/c/256f7d4c11235d0569f78413c41dc89d2dc1557c"
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}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-191"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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