[CVE-2026-74362][LOW] ext2: fix ignored return value of generic_write_sync() [ Upstream

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-74362
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ext2: fix ignored return value of generic_write_sync() [ Upstream
Commit: 8990dbb7065b0b002b1e58b9091a5b61f5e94dbe
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8990dbb7065b0b002b1e58b9091a5b61f5e94dbe
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74362
Analysis date: Sun, 16 Aug 2026 07:22:39 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
ext2 direct I/O writes with O_SYNC or O_DSYNC could incorrectly report success when generic_write_sync or filemap_write_and_wait_range failed, causing a local data durability and integrity reporting issue without memory corruption or privilege escalation.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74362 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74362

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-74362	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L';CWE-252;CWE-754;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N';BEST CVSS score: '3.6';DESCR 'An ext2 direct I/O write on an O_SYNC or O_DSYNC file could report success even when the final sync step failed. This happens because ext2_dio_write_iter did not propagate errors from generic_write_sync and could also lose an error from filemap_write_and_wait_range. The main impact is integrity risk for stored data because applications may believe data was durably written when the kernel actually observed a sync or writeback failure. For the CVSS the PR:L is used because a local process needs write access to an affected ext2 file, but no administrative privileges are normally required for the file write itself. The issue is not directly network reachable and does not indicate memory corruption or privilege escalation. Impact is limited to possible data integrity loss and in a conservative case limited availability impact for affected files or workloads.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-74362 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	KASAN DISK SIMPLEFIX  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=2

## 1. ActionableScore

* Conservative score: **2**
* Paranoid score: **2**
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: **+1**. A local process with write permission to an affected ext2 file can use O_SYNC or O_DSYNC direct I/O.
* Integrity impact plausible: **+1**. Userspace may receive a successful write result even though sync or writeback failed, creating a data durability and integrity reporting issue.
* Important filesystem/storage path: **+1**. The bug is in filesystem direct-write and sync error propagation.

Subtracting signals:

* Hard or unreliable condition required: **-1**. The visible impact requires a sync or writeback failure, not merely a normal write.
* No memory corruption, no UAF, no OOB, no privilege escalation primitive: **+0**. The patch only fixes ignored return values.

Total: **2**

## 3. Reachability analysis

A local user or process can trigger the relevant code path only if it can write to a file on an ext2 filesystem using O_SYNC or O_DSYNC direct I/O. No network reachability is indicated. Namespaces or containers do not materially increase severity unless they expose writable ext2 storage where durability semantics matter. The affected path is not a broad default attack surface because ext2 is less common than ext4/xfs and the harmful result depends on an actual sync or writeback error.

## 4. Severity interpretation

This behaves like an ordinary Low-like or weak Moderate correctness/security issue, not an Important-class vulnerability. The realistic impact is incorrect success reporting to userspace and possible data integrity loss for affected writes. There is no demonstrated memory corruption, no kernel crash, no page-cache ownership bypass, and no plausible privilege escalation path from the supplied patch.

## 5. One-sentence report phrase

ext2 direct I/O writes with O_SYNC or O_DSYNC could incorrectly report success when generic_write_sync or filemap_write_and_wait_range failed, causing a local data durability and integrity reporting issue without memory corruption or privilege escalation.

## 6. Manual review recommendation

**NO MANUAL CHECK NEEDED**

This can be auto-closed or handled in deferred mode for most security triage workflows because the score is low, the issue is local and condition-dependent, and the patch does not show memory corruption, LPE, network exposure, or a sensitive security-boundary bypass.

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UPSTREAM PATCH SUMMARY
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Patch: ext2: fix ignored return value of generic_write_sync() [ Upstream
Commit: 8990dbb7065b0b002b1e58b9091a5b61f5e94dbe
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8990dbb7065b0b002b1e58b9091a5b61f5e94dbe

Changed files:
  fs/ext2/file.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8990dbb7065b0b002b1e58b9091a5b61f5e94dbe

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DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74362 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74362

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L
  The Best / paranoid CVSS score: 3.6

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: unknown
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).