CVE-2025-39900 (GCVE-0-2025-39900)
Vulnerability from cvelistv5
Published
2025-10-01 07:42
Modified
2025-10-01 07:42
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y
syzbot reported a WARNING in est_timer() [1]
Problem here is that with CONFIG_PREEMPT_RT=y, timer callbacks
can be preempted.
Adopt preempt_disable_nested()/preempt_enable_nested() to fix this.
[1]
WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 __seqprop_assert include/linux/seqlock.h:221 [inline]
WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__seqprop_assert include/linux/seqlock.h:221 [inline]
RIP: 0010:est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93
Call Trace:
<TASK>
call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers kernel/time/timer.c:2372 [inline]
__run_timer_base+0x648/0x970 kernel/time/timer.c:2384
run_timer_base kernel/time/timer.c:2393 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
handle_softirqs+0x22c/0x710 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
run_ktimerd+0xcf/0x190 kernel/softirq.c:1043
smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/core/gen_estimator.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "d2d6422f8bd17c6bb205133e290625a564194496",
"versionType": "git"
},
{
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"status": "affected",
"version": "d2d6422f8bd17c6bb205133e290625a564194496",
"versionType": "git"
},
{
"lessThan": "9f74c0ea9b26d1505d55b61e36b1623dd347e1d1",
"status": "affected",
"version": "d2d6422f8bd17c6bb205133e290625a564194496",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12"
},
{
"lessThan": "6.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.46",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.16.*",
"status": "unaffected",
"version": "6.16.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.17",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.46",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.16.6",
"versionStartIncluding": "6.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.17",
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y\n\nsyzbot reported a WARNING in est_timer() [1]\n\nProblem here is that with CONFIG_PREEMPT_RT=y, timer callbacks\ncan be preempted.\n\nAdopt preempt_disable_nested()/preempt_enable_nested() to fix this.\n\n[1]\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 __seqprop_assert include/linux/seqlock.h:221 [inline]\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\nModules linked in:\nCPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025\n RIP: 0010:__seqprop_assert include/linux/seqlock.h:221 [inline]\n RIP: 0010:est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\nCall Trace:\n \u003cTASK\u003e\n call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747\n expire_timers kernel/time/timer.c:1798 [inline]\n __run_timers kernel/time/timer.c:2372 [inline]\n __run_timer_base+0x648/0x970 kernel/time/timer.c:2384\n run_timer_base kernel/time/timer.c:2393 [inline]\n run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403\n handle_softirqs+0x22c/0x710 kernel/softirq.c:579\n __do_softirq kernel/softirq.c:613 [inline]\n run_ktimerd+0xcf/0x190 kernel/softirq.c:1043\n smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160\n kthread+0x70e/0x8a0 kernel/kthread.c:463\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e"
}
],
"providerMetadata": {
"dateUpdated": "2025-10-01T07:42:47.785Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/a22ec2ee824be30803068a52f78f7ffe3bc879fb"
},
{
"url": "https://git.kernel.org/stable/c/e79923824c48b930609680be04cb29253fc4a17d"
},
{
"url": "https://git.kernel.org/stable/c/9f74c0ea9b26d1505d55b61e36b1623dd347e1d1"
}
],
"title": "net_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-39900",
"datePublished": "2025-10-01T07:42:47.785Z",
"dateReserved": "2025-04-16T07:20:57.146Z",
"dateUpdated": "2025-10-01T07:42:47.785Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.1",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2025-39900\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-10-01T08:15:32.740\",\"lastModified\":\"2025-10-02T19:12:17.160\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y\\n\\nsyzbot reported a WARNING in est_timer() [1]\\n\\nProblem here is that with CONFIG_PREEMPT_RT=y, timer callbacks\\ncan be preempted.\\n\\nAdopt preempt_disable_nested()/preempt_enable_nested() to fix this.\\n\\n[1]\\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 __seqprop_assert include/linux/seqlock.h:221 [inline]\\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\\nModules linked in:\\nCPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025\\n RIP: 0010:__seqprop_assert include/linux/seqlock.h:221 [inline]\\n RIP: 0010:est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\\nCall Trace:\\n \u003cTASK\u003e\\n call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747\\n expire_timers kernel/time/timer.c:1798 [inline]\\n __run_timers kernel/time/timer.c:2372 [inline]\\n __run_timer_base+0x648/0x970 kernel/time/timer.c:2384\\n run_timer_base kernel/time/timer.c:2393 [inline]\\n run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403\\n handle_softirqs+0x22c/0x710 kernel/softirq.c:579\\n __do_softirq kernel/softirq.c:613 [inline]\\n run_ktimerd+0xcf/0x190 kernel/softirq.c:1043\\n smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160\\n kthread+0x70e/0x8a0 kernel/kthread.c:463\\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\\n \u003c/TASK\u003e\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/9f74c0ea9b26d1505d55b61e36b1623dd347e1d1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a22ec2ee824be30803068a52f78f7ffe3bc879fb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e79923824c48b930609680be04cb29253fc4a17d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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