CVE-2026-45977

System crash via firmware-log teardown race

Published May 27, 2026 · Updated May 27, 2026

Use-after-free in Linux Kernel fbnic logging in 6.17 through 6.18.13 and 6.19 through 6.19.3 allows local users to crash the system. fbnic_fw_log_free() releases log->data_start before mailbox and interrupt teardown, so fbnic_fw_log_write() can resume after its readiness check and access the freed buffer. Exploitation requires low-privileged local access and an fbnic device whose mailbox activity overlaps removal, with the documented impact limited to a system crash.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel fbnic logging in 6.17 through 6.18.13 and 6.19 through 6.19.3 allows local users to crash the system. fbnic_fw_log_free() releases log->data_start before mailbox and interrupt teardown, so fbnic_fw_log_write() can resume after its readiness check and access the freed buffer. Exploitation requires low-privileged local access and an fbnic device whose mailbox activity overlaps removal, with the documented impact limited to a system crash.

The record

CVE
CVE-2026-45977
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=6.17
  2. Affected versionversion=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <223cfef4812bdfa5ac5c1aa761cdba03cfe2c9cd
  3. Affected versionversion=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <5f10ab3643c58a22fbaee92c4701b00fcb4a465d
  4. Affected versionversion=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <ee5492fd88cfc079c19fbeac78e9e53b7f6c04f3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.17; version=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <223cfef4812bdfa5ac5c1aa761cdba03cfe2c9cd; version=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <5f10ab3643c58a22fbaee92c4701b00fcb4a465d; version=ecc53b1b46c892d2e3cf3cf4393b6d219dc4ae3f <ee5492fd88cfc079c19fbeac78e9e53b7f6c04f3

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

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

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Your stack

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