CVE-2025-21845

Kernel crash via one-byte SST NOR writes

Published Mar 12, 2025 · Updated Jun 1, 2026

Improper write handling in Linux kernel 6.12 through 6.12.16 and 6.13 through 6.13.4 allows local users to crash the kernel. The sst_nor_write_data() function uses a one-byte transfer length instead of the supplied byte count, so a multi-byte request returns short and triggers the kernel warning path. Exploitation requires local access to an affected SST SPI-NOR device and a write exceeding one byte; the reported consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper write handling in Linux kernel 6.12 through 6.12.16 and 6.13 through 6.13.4 allows local users to crash the kernel. The sst_nor_write_data() function uses a one-byte transfer length instead of the supplied byte count, so a multi-byte request returns short and triggers the kernel warning path. Exploitation requires local access to an affected SST SPI-NOR device and a write exceeding one byte; the reported consequence is a kernel crash.

The record

CVE
CVE-2025-21845
Published
Mar 12, 2025
Updated
Jun 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 1, 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=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <539bd20352832b9244238a055eb169ccf1c41ff6
  2. Affected versionversion=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <9553391f32f8c43e12fc7c04e1035160b5ea20bf
  3. Affected versionversion=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <bb1accc7e0f688886f0c634f2e878b8ac4ee6a58
  4. Affected versionversion=6.12
  5. Affected versionversion=b7cd63d13faef7ca5cf31ffa45ebf08829e4c9a7 <f7c14993dc2f1eca661975c0ff90a6e2098ecd41
  6. Affected versionversion=b925a5787b6e1d05731eb2dcc31dcaafc40ec2b6 <f791837015a0d20f584d0ed368393f119a00018f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <539bd20352832b9244238a055eb169ccf1c41ff6; version=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <9553391f32f8c43e12fc7c04e1035160b5ea20bf; version=18bcb4aa54eab75dce41e5c176a1c2bff94f0f79 <bb1accc7e0f688886f0c634f2e878b8ac4ee6a58; version=6.12; version=b7cd63d13faef7ca5cf31ffa45ebf08829e4c9a7 <f7c14993dc2f1eca661975c0ff90a6e2098ecd41; version=b925a5787b6e1d05731eb2dcc31dcaafc40ec2b6 <f791837015a0d20f584d0ed368393f119a00018f

Published CVSS scores

5.5CISA-ADPCVSS: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.

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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

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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