VulnerabilityPublished 11 Sep 2026Updated 30 Oct 2026

CVE-2026-89480: Linux kernel · nvme-tcp: reject a read that transferred too few bytes

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in fca3ebb63e5c82561cd9934365dcc0d068008006 : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:49 UTC

CVSS 3.1 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (Linux)	CVSS 3.1	7.5

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch

Available – fixed in fca3ebb63e5c82561cd9934365dcc0d068008006, b674af31d044a86bd094ba8bb8f2bb92fb49aac5, aa107e3a68f4af177d60f2d87679e7f67179a36c +5

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

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

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: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < fca3ebb63e5c82561cd9934365dcc0d068008006	Fixed in fca3ebb63e5c82561cd9934365dcc0d068008006
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < b674af31d044a86bd094ba8bb8f2bb92fb49aac5	Fixed in b674af31d044a86bd094ba8bb8f2bb92fb49aac5
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < aa107e3a68f4af177d60f2d87679e7f67179a36c	Fixed in aa107e3a68f4af177d60f2d87679e7f67179a36c
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < a5c1bb0fb1bab2f24a081339c145870697f6d220	Fixed in a5c1bb0fb1bab2f24a081339c145870697f6d220
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < 99066cf9bba175f610ceb61a35f6fc9fbc33ff65	Fixed in 99066cf9bba175f610ceb61a35f6fc9fbc33ff65
LinuxLinux	Affected ≥ 3f2304f8c6d6ed97849057bd16fee99e434ca796, < 832a685efeb5d925ee7d30011d2dbe45f81447a3	Fixed in 832a685efeb5d925ee7d30011d2dbe45f81447a3

Description

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: reject a read that transferred too few bytes nvme_tcp_recv_data() completes a request once the current C2HData PDU has been consumed. Nothing compares the total bytes received against the length the command asked for: struct nvme_tcp_request has no receive-side counter, queue->data_remaining is per queue, and blk_mq_end_request() completes for blk_rq_bytes(rq) unconditionally with no residual concept anywhere above. A controller can therefore answer a 4096-byte read with 512 bytes and have it reported as a complete read; user space then gets 4096 bytes of which 3584 are whatever was already in the page. I reproduced that with a test target. Count the bytes received and refuse to complete a successful read whose count does not match, at the two NVME_TCP_F_DATA_SUCCESS paths and in nvme_tcp_process_nvme_cqe(). The success test shifts req->status right by one, because the driver keeps the wire value there and shifts it on completion, so the check must see what the completion path will see. Only REQ_OP_READ is checked, because there the length comes from the sectors the request covers; a passthrough command is built by its submitter, which picks both command and buffer, so the kernel has nothing to compare against.

References

Community reviews

Loading reviews…