CVE-2026-89830

Block-count leak via failed data allocation

Published Sep 16, 2026 · Updated Sep 16, 2026

Resource-accounting error in Linux 6.9 allows attackers to leak f2fs valid-block counts via a data-block allocation failure. In __allocate_data_block(), the kernel increments total_valid_block_count and i_blocks but fails to decrement them when later allocation fails. The path requires allocation of a new f2fs data block to fail; published material establishes neither attacker control of that failure nor a further consequence.

CVSS severityUnavailable
Unscored
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource-accounting error in Linux 6.9 allows attackers to leak f2fs valid-block counts via a data-block allocation failure. In __allocate_data_block(), the kernel increments total_valid_block_count and i_blocks but fails to decrement them when later allocation fails. The path requires allocation of a new f2fs data block to fail; published material establishes neither attacker control of that failure nor a further consequence.

The record

CVE
CVE-2026-89830
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=6.9
  2. Affected versionversion=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <0f9af07ecc1ab486038373db6ae0436c5d674b19
  3. Affected versionversion=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <2d50b6d47e5671ff6a25834c5906d443356191f0
  4. Affected versionversion=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <931e1aa4d44c52ff8e0feb38420a8827c62e886b
  5. Affected versionversion=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <dde99df5a9d3b0ca6ac0a86f98799685f7399432

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.9; version=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <0f9af07ecc1ab486038373db6ae0436c5d674b19; version=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <2d50b6d47e5671ff6a25834c5906d443356191f0; version=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <931e1aa4d44c52ff8e0feb38420a8827c62e886b; version=7d009e048d7cfcc21d400f2aba4c8bacbdebbd47 <dde99df5a9d3b0ca6ac0a86f98799685f7399432

Published CVSS scores

No CVSS assessment is available in this record.

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
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

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Your stack

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