VulnerabilityPublished 25 Jul 2026Updated 21 Oct 2026

CVE-2026-64320: Linux kernel · Out-of-bounds Read

Source GCVE Database

Authoritative record:CVE-2026-64320· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical · fixed in a29b316b9bbfd269f323ab4ba9906a894025680f : patch Linux kernel as a priority.

Data as of 27 Oct 2026, 05:11 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in a29b316b9bbfd269f323ab4ba9906a894025680f, 56c021a0869260d04c4b65d1471936aaf9177114, 53cd102a7a56079b11b897835bd9b94c14e6322c +2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-qw96-j6m6-f3qh

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ a07b4970f464f13640e28e16dad6cfa33647cc99, < a29b316b9bbfd269f323ab4ba9906a894025680f	Fixed in a29b316b9bbfd269f323ab4ba9906a894025680f
LinuxLinux	Affected ≥ a07b4970f464f13640e28e16dad6cfa33647cc99, < 56c021a0869260d04c4b65d1471936aaf9177114	Fixed in 56c021a0869260d04c4b65d1471936aaf9177114
LinuxLinux	Affected ≥ a07b4970f464f13640e28e16dad6cfa33647cc99, < 53cd102a7a56079b11b897835bd9b94c14e6322c	Fixed in 53cd102a7a56079b11b897835bd9b94c14e6322c
LinuxLinux	Affected ≥ a07b4970f464f13640e28e16dad6cfa33647cc99, < 33b974eb626154ae9348f2bac7de84cb2a3d9dd4	Fixed in 33b974eb626154ae9348f2bac7de84cb2a3d9dd4
LinuxLinux	Affected ≥ a07b4970f464f13640e28e16dad6cfa33647cc99, < 8ae9bb92fc9a712a8d32da9c5fd657101f9b260b	Fixed in 8ae9bb92fc9a712a8d32da9c5fd657101f9b260b
LinuxLinux	Affected =4.8	Fixed in–

AI-suggested

The vulnerability has been resolved in the Linux kernel by validating the host-supplied offset against the log page size, capping the copy length, and zero-filling the remainder of the transfer buffer. Users should apply the official Linux kernel updates once available to address this issue. Until patched, restricting network access to nvmet targets and disabling the discovery controller if not needed may reduce exposure.

Description

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.

Impact

An unauthenticated remote attacker with network access to the nvmet target can exploit this vulnerability to read out-of-bounds kernel memory, potentially leaking sensitive kernel pointers and other data. Additionally, crafted requests can cause kernel crashes or panics, leading to denial of service. There is no indication of code execution or privilege escalation from the provided data.

Summary

The Linux kernel's nvmet_execute_disc_get_log_page() function improperly validates the host-supplied 64-bit Log Page Offset, only checking for dword alignment but not ensuring it is within the allocated buffer size. This leads to an out-of-bounds heap read when the offset plus requested data length exceeds the discovery log page buffer. Since the discovery controller is unauthenticated, any remote peer with network access to the nvmet target can trigger this pre-authentication. An attacker can leak kernel memory contents, including kernel pointers, or cause kernel crashes by referencing unmapped memory. The fix involves validating the offset against the log page size, limiting the copy length to available data, and zero-filling any remaining bytes to prevent leakage of transport scatter-gather list contents.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Jul 2026, 23:34 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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