CVE-2026-90257

Kernel-memory disclosure via unbounded build-information string

Published Sep 17, 2026 · Updated Sep 17, 2026

Out-of-bounds reading in Linux virtio_bt allows attackers to expose kernel memory through malformed Zephyr backend responses. The virtbt_setup_zephyr() function formats bytes after the response status as an unbounded string, reading adjacent slab memory when the response contains only status or lacks a NUL terminator. Exposure requires Zephyr-specific virtio Bluetooth setup and a malformed backend response; the leaked bytes reach the kernel log and firmware-info debugfs file, with disclosure dependent on access to those outputs.

CVSS severity4.8
Medium
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Out-of-bounds reading in Linux virtio_bt allows attackers to expose kernel memory through malformed Zephyr backend responses. The virtbt_setup_zephyr() function formats bytes after the response status as an unbounded string, reading adjacent slab memory when the response contains only status or lacks a NUL terminator. Exposure requires Zephyr-specific virtio Bluetooth setup and a malformed backend response; the leaked bytes reach the kernel log and firmware-info debugfs file, with disclosure dependent on access to those outputs.

The record

CVE
CVE-2026-90257
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.13
  2. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <0e388d805233a883a31271676eae6031dfc9e898
  3. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <502adc06ba76dee19c292ae4a07d74d202fe734d
  4. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <54e9387eb7546eaa6f600220599d55740956ffc3
  5. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <84ea9c99874804f5ca13f35bbc186ba93902f30f
  6. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <be1e3df2c49c91b0a052c6563884e8d39bd768b2
  7. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <d08c99abf06133a7829d46627e77e3315ca974d2
  8. Affected versionversion=afd2daa26c7abd734d78bd274fc6c59a15e61063 <fb445b3466a8d1c7a0b0d0676fb475e3ce22d94e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <0e388d805233a883a31271676eae6031dfc9e898; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <502adc06ba76dee19c292ae4a07d74d202fe734d; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <54e9387eb7546eaa6f600220599d55740956ffc3; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <84ea9c99874804f5ca13f35bbc186ba93902f30f; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <be1e3df2c49c91b0a052c6563884e8d39bd768b2; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <d08c99abf06133a7829d46627e77e3315ca974d2; version=afd2daa26c7abd734d78bd274fc6c59a15e61063 <fb445b3466a8d1c7a0b0d0676fb475e3ce22d94e

Published CVSS scores

4.0Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
3.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started