Linux Kernel: Out-of-bounds Read (CVE-2026-64320)
Published Last modified Sources: Ubuntu, HKCERT, SUSE, Red Hat, CVE.org, Debian LTS, Msrc Update Guide, BSI
What is affected, what to do
A flaw was found in the Linux kernel's nvmet subsystem. An unauthenticated remote attacker could exploit an out-of-bounds heap read vulnerability in the Discovery Get Log Page function.
Update Linux Kernel to version 6.1.191, Linux Kernel to version 6.6.160, Linux Kernel to version 6.12.96.
- Affected
- Linux Kernel
lt 4.8..6.1.191 - Linux Kernel
lt 6.2..6.6.160 - Linux Kernel
lt 6.7..6.12.96 - Linux Kernel
lt 6.13..6.18.39 - Linux Kernel
lt 6.19..7.1.4
- Linux Kernel
- Fixed in
- Linux Kernel
6.1.191 - Linux Kernel
6.6.160 - Linux Kernel
6.12.96 - Linux Kernel
6.18.39 - Linux Kernel
7.1.4 - Linux Kernel
7.2
- Linux Kernel
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Metrics
9.1
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
9.1
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: Ubuntu, HKCERT, SUSE, Red Hat, CVE.org, Debian LTS, Msrc Update Guide, BSI
0.8 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 56.7
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 92.38 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 9.1 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 9.1
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.8 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 56.7
- High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 16 October 2026
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-125
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
A flaw was found in the Linux kernel's nvmet subsystem. An unauthenticated remote attacker could exploit an out-of-bounds heap read vulnerability in the Discovery Get Log Page function. By sending a specially crafted request with a manipulated offset, an attacker could read sensitive kernel memory, leading to information disclosure of kernel pointers. This vulnerability could also cause a denial of service by crashing the target host.
Source: Ubuntu Security Notices, HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, suse_csaf, redhat_csaf, cvelistv5, NVD (NIST), Debian LTS Advisories, Microsoft Security Update Guide, BSI WID Portal, BSI CSAF
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Linux | Linux |
|
|
| IBM | QRadar SIEM |
|
|
Vendors and products
Affected operating systems
| Linux | ubuntu | linux | noble |
| Linux | debian | linux-6.12 | bookworm |
| Linux | ubuntu | linux-aws | noble |
| Linux | ubuntu | linux-aws-fips | noble |
| Linux | ubuntu | linux-azure | noble |
| Linux | ubuntu | linux-azure-fde | noble |
| Linux | ubuntu | linux-azure-fips | noble |
| Linux | ubuntu | linux-fips | noble |
| Linux | ubuntu | linux-gcp | noble |
| Linux | ubuntu | linux-gcp-fips | noble |
| Linux | ubuntu | linux-gke | noble |
| Linux | ubuntu | linux-gkeop | noble |
| Linux | ubuntu | linux-ibm | noble |
| Linux | ubuntu | linux-lowlatency | noble |
| Linux | ubuntu | linux-oracle | noble |
| Linux | ubuntu | linux-realtime | noble |
| Linux | linux | linux_kernel | — |
Weakness classes (CWE)
CWE-125Out-of-bounds Read
Base
The product reads data past the end, or before the beginning, of the intended buffer.
Entry at MITRE CWE-125
References & sources
- git.kernel.orgstable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4Patch
- git.kernel.orgstable/c/56c021a0869260d04c4b65d1471936aaf9177114Patch
- git.kernel.orgstable/c/a29b316b9bbfd269f323ab4ba9906a894025680fPatch
- git.kernel.orgstable/c/53cd102a7a56079b11b897835bd9b94c14e6322cPatch
- git.kernel.orgstable/c/8ae9bb92fc9a712a8d32da9c5fd657101f9b260b
- git.kernel.orgstable/c/ff815b5e8688dcf68529b7f0fde8de5847f63f1e
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedLinux
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/64xxx/CVE-2026-64320.json">CVE-2026-64320</a>Reference added —https://git.kernel.org/stable/c/ff815b5e8688dcf68529b7f0fde8de5847f63f1eSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record modifiedLinux
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/64xxx/CVE-2026-64320.json">CVE-2026-64320</a>Reference added —https://git.kernel.org/stable/c/8ae9bb92fc9a712a8d32da9c5fd657101f9b260bSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record modifiedCISA ADP
Weakness type: CWE-125
Show the original change
Individual changes of this event as published by NVD Type Action Before After Weakness type (CWE) added —CWE-125Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Record modifiedLinux
New references:Show 12 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4Reference added —https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322cReference added —https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114Reference added —https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680fReference removed https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4—Reference removed https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322c—Reference removed https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114—Reference removed https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680f—Reference type removed https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4 Types: Patch—Reference type removed https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322c Types: Patch—Reference type removed https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114 Types: Patch—Reference type removed https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680f Types: Patch—Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: none known, automatable: yes
Show the original change
Individual changes of this event as published by NVD Type Action Before After SSVC assessment added —{"id":"CVE-2026-64320","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:39:04.867020Z"}Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Show 2 older changes
Record modifiedLinux
1 individual change: Affected versions (publisher)
Show the original change
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) changed Linux, LinuxLinux, LinuxSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
ReceivedLinux
Description added or changed
New references:Show 6 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Linux, LinuxDescription added —In the Linux kernel, the following vulnerability has been resolved: nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page nvmet_execute_disc_get_log_page() validates only the dword alignment of the host-supplied Log Page Offset (lpo). The 64-bit offset is then added to a small kzalloc'd buffer that holds the discovery log page and the result is passed straight to nvmet_copy_to_sgl(), which memcpy()s data_len bytes out to the host with no source-side bound check: u64 offset = nvmet_get_log_page_offset(req->cmd); /* 64-bit host */ size_t data_len = nvmet_get_log_page_len(req->cmd); /* 32-bit host */ ... if (offset & 0x3) { ... } /* only check */ ... alloc_len = sizeof(*hdr) + entry_size * discovery_log_entries(req); buffer = kzalloc(alloc_len, GFP_KERNEL); ... status = nvmet_copy_to_sgl(req, 0, buffer + offset, data_len); The Discovery controller is unauthenticated -- nvmet_host_allowed() returns true unconditionally for the discovery subsystem -- so the call is reachable pre-authentication by any TCP/RDMA/FC peer that can reach the nvmet target. With a discovery log page of ~1 KiB, an attacker requesting up to 4 KiB starting at offset == alloc_len reads the next slab page out and gets its content returned over the fabric (an empirical run on a default nvmet-tcp loopback target leaked 81 canonical kernel pointers in one Get Log Page response). Pointing the offset at unmapped kernel memory faults the in-kernel memcpy and crashes (or panics, on panic_on_oops=1) the target host instead. The attacker-controlled source-side offset pattern "nvmet_copy_to_sgl(req, 0, buffer + ATTACKER_OFFSET, ...)" is unique to nvmet_execute_disc_get_log_page in the entire nvmet codebase: every other Get Log Page handler in admin-cmd.c either ignores lpo (and silently starts every response at offset 0) or tracks a local destination offset with a fixed source pointer. Validate the host-supplied offset against the log page size, cap the copy length to what is actually available, and zero-fill any remainder of the host transfer buffer. The zero-fill matches the existing short-response pattern in nvmet_execute_get_log_changed_ns() (admin-cmd.c) and prevents leaking transport SGL contents when the host asks for more bytes than the log page contains.Reference added —https://git.kernel.org/stable/c/33b974eb626154ae9348f2bac7de84cb2a3d9dd4Reference added —https://git.kernel.org/stable/c/53cd102a7a56079b11b897835bd9b94c14e6322cReference added —https://git.kernel.org/stable/c/56c021a0869260d04c4b65d1471936aaf9177114Reference added —https://git.kernel.org/stable/c/a29b316b9bbfd269f323ab4ba9906a894025680fSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-64320"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-64320.svg?lang=en" alt="CVE-2026-64320 – NEOSEC Intel" height="20"></a>