CVE-2026-64086 — hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer adm1266_pmbus_block_xfer() sets up the read transaction with .buf = data->read_buf, .len = ADM1266_PMBUS_BLOCK_MAX + 2, but read_buf in struct adm1266_data is declared as u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1]; For a max-length block response (length byte = 255 + up to 1 PEC byte), the i2c controller is told to write 257 bytes into a 256-byte buffer, putting one byte past the end of read_buf. The same response also makes the subsequent PEC compare if (crc != msgs[1].buf[msgs[1].buf[0] + 1]) read a byte beyond the array. Bump the read_buf declaration to ADM1266_PMBUS_BLOCK_MAX + 2 so the buffer can hold the length byte, up to 255 payload bytes, and the PEC byte the i2c_msg length already accounts for.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 5.10≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < 487566cb1ccdf3756fdd7bf8d875e612ff3169bb≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < a6c802145a8de0830bca803c6d415f7e9e683624≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < 2279c342d94eca225bf9f301c8806a05a1c81619≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < d94ceb16e55b6d8019ab069e357c76ac42f0ffbc≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < 528a9f88e88502d0c2f2052a279415074cd83715≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < 472744f69d25a2d5111ad62f1d62579dce2c13c8 and 1 more≥ 407dc802a9c0809ca6a48de4b4c63305eb84ef56 and < 397d3f523bfff2f4e3dacf9b1339bd76dc207f78 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 7.1-rc4≥ 5.10 and < 5.10.258version 7.1-rc3version 7.1-rc2version 7.1-rc1≥ 6.19 and < 7.0.11≥ 6.13 and < 6.18.34≥ 6.7 and < 6.12.92 and 3 more≥ 6.2 and < 6.6.142≥ 5.16 and < 6.1.175≥ 5.11 and < 5.15.209 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
8 on the record
- git.kernel.org/stable/c/bd5be3fa5de6dbf61f1b3cec6b79c2c2f8065694
- git.kernel.org/stable/c/d94ceb16e55b6d8019ab069e357c76ac42f0ffbc
- git.kernel.org/stable/c/397d3f523bfff2f4e3dacf9b1339bd76dc207f78
- git.kernel.org/stable/c/487566cb1ccdf3756fdd7bf8d875e612ff3169bb
- git.kernel.org/stable/c/a6c802145a8de0830bca803c6d415f7e9e683624
- git.kernel.org/stable/c/2279c342d94eca225bf9f301c8806a05a1c81619
- git.kernel.org/stable/c/472744f69d25a2d5111ad62f1d62579dce2c13c8
- git.kernel.org/stable/c/528a9f88e88502d0c2f2052a279415074cd83715
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 9h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 9h
- Unknown CVE-2026-98431 RDMA/uverbs: Fix mmap_lock/disassociation_lock circular dependency 1d
- Unknown CVE-2026-98430 RDMA/efa: Keep admin queues alive while IRQ is registered 1d
- Unknown CVE-2026-98429 RDMA/efa: Keep EQ resources alive while IRQ is registered 1d
- Unknown CVE-2026-98428 ALSA: usb: 6fire: Avoid embedded URBs 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No FIRST EPSS score.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-64086 is "hwmon: (pmbus/adm1266) include PEC byte in pmbus_block_xfer read buffer", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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