counter: rz-mtu3-cnt: prevent counter from being toggled multiple times
In the Linux kernel, the following vulnerability has been resolved: counter: rz-mtu3-cnt: prevent counter from being toggled multiple times Runtime PM counter is incremented / decremented each time the sysfs enable file is written to. If user writes 0 to the sysfs enable file multiple times, runtime PM usage count underflows, generating the following message. rz-mtu3-counter rz-mtu3-counter.0: Runtime PM usage count underflow! At the same time, hardware registers end up being accessed with clocks off in rz_mtu3_terminate_counter() to disable an already disabled channel. If user writes 1 to the sysfs enable file multiple times, runtime PM usage count will be incremented each time, requiring the same number of 0 writes to get it back to 0. If user writes 0 to the sysfs enable file while PWM is in progress, PWM is stopped without counter being the owner of the underlying MTU3 channel. Check against the cached count_is_enabled value and exit if the user is trying to set the same enable value.
- Published
- May 1, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 5th percentile
- CWE
- —
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernel6.4 and later · before 6.6.134
- linux linux kernel6.7 and later · before 6.12.81
- linux linux kernel6.13 and later · before 6.18.22
- linux linux kernel6.19 and later · before 6.19.12
- linux linux kernel7.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 6.4affected
- 0be8907359df4c62319f5cb2c6981ff0d9ebf35a and later · before 885aa739a07ab45e90dfa997205acec97979ce4eaffected · git
- 0be8907359df4c62319f5cb2c6981ff0d9ebf35a and later · before ced8b48420eddb1251f93c22dc23fa136490b3cdaffected · git
- 0be8907359df4c62319f5cb2c6981ff0d9ebf35a and later · before e07237df8538b0ae98dce112e4f6db093d767f80affected · git
- 0be8907359df4c62319f5cb2c6981ff0d9ebf35a and later · before f5f6f06d7e6d262026578b59ba7426eb04acce5daffected · git
- 0be8907359df4c62319f5cb2c6981ff0d9ebf35a and later · before 67c3f99bed6f422ba343d2b70a2eeeccdfd91befaffected · git
- before 6.4not affected · semver
- 6.6.134 and later · up to and including 6.6.*not affected · semver
- 6.12.81 and later · up to and including 6.12.*not affected · semver
- 6.18.22 and later · up to and including 6.18.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:13 | linux | before 6.12.85-1 | 6.12.85-1 |
| Debian:14 | linux | before 6.19.12-1 | 6.19.12-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 67c3f99bed6f422ba343d2b70a2eeeccdfd91bef | Vendor (CNA) |
| Linux Linux | 885aa739a07ab45e90dfa997205acec97979ce4e | Vendor (CNA) |
| Linux Linux | ced8b48420eddb1251f93c22dc23fa136490b3cd | Vendor (CNA) |
| Linux Linux | e07237df8538b0ae98dce112e4f6db093d767f80 | Vendor (CNA) |
| Linux Linux | f5f6f06d7e6d262026578b59ba7426eb04acce5d | Vendor (CNA) |
| debian:linux | 6.12.85-1 · Debian:13 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/67c3f99bed6f422ba343d2b70a2eeeccdfd91bef
- git.kernel.org/stable/c/885aa739a07ab45e90dfa997205acec97979ce4e
- git.kernel.org/stable/c/ced8b48420eddb1251f93c22dc23fa136490b3cd
- git.kernel.org/stable/c/e07237df8538b0ae98dce112e4f6db093d767f80
- git.kernel.org/stable/c/f5f6f06d7e6d262026578b59ba7426eb04acce5d
Vendor advisories and official records. Exploit/PoC links are deliberately left out.