CVE-2026-72163

ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits

Published Aug 15, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits

[BUG]
A direct write over unwritten extents can panic the kernel in
ocfs2_assure_trans_credits() when the journal aborts during DIO
completion. The crash is a general protection fault from a NULL pointer
dereference.

[CAUSE]
ocfs2_dio_end_io_write() loops over a direct write's unwritten extents,
marking each written under a single journal handle. If the journal
aborts (for example after an I/O error) while the extent tree is being
updated, the handle is left aborted with its transaction pointer
cleared. The extent merge treats that failure as not critical and
reports success, so the loop keeps using the handle.
ocfs2_assure_trans_credits() reads the handle's remaining credits
without first checking whether the handle is aborted, and that read
dereferences the cleared transaction pointer.

[FIX]
A journal abort is recorded in the handle itself, so callers are
expected to test the handle rather than rely on a returned error.
Make ocfs2_assure_trans_credits() do that, as the other ocfs2 journal
helpers already do, and return -EROFS when the handle is aborted.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8876-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8877-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8878-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8879-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8888-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8889-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-2 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8888-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8875-2 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8887-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8917-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8918-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9003-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9024-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9025-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9026-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9029-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-9040-1 Linux kernel (Low Latency NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9043-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-9066-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9091-1 Linux kernel (NVIDIA Tegra) vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-476
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits [BUG] A direct write over unwritten extents can panic the kernel in ocfs2_assure_trans_credits() when the journal aborts during DIO completion. The crash is a general protection fault from a NULL pointer dereference. [CAUSE] ocfs2_dio_end_io_write() loops over a direct write's unwritten extents, marking each written under a single journal handle. If the journal aborts (for example after an I/O error) while the extent tree is being updated, the handle is left aborted with its transaction pointer cleared. The extent merge treats that failure as not critical and reports success, so the loop keeps using the handle. ocfs2_assure_trans_credits() reads the handle's remaining credits without first checking whether the handle is aborted, and that read dereferences the cleared transaction pointer. [FIX] A journal abort is recorded in the handle itself, so callers are expected to test the handle rather than rely on a returned error. Make ocfs2_assure_trans_credits() do that, as the other ocfs2 journal helpers already do, and return -EROFS when the handle is aborted.
Title ocfs2: fix NULL h_transaction deref in ocfs2_assure_trans_credits
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Nov 6, 2026, 4:55 PM
Reserved
Aug 9, 2026, 3:40 AM
Status
Received
Published
Aug 15, 2026, 6:21 AM
Modified
Nov 6, 2026, 5:19 PM
Severity
Moderate
Public date
Aug 15, 2026, 12:00 AM