Linux Kernel up to 6.6.94/6.12.34/6.15.3 ext4 ext4_dirty_journalled_data null pointer dereference

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5.0$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.6.94/6.12.34/6.15.3. Impacted is the function ext4_dirty_journalled_data of the component ext4. The manipulation leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2025-38220. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.6.94/6.12.34/6.15.3. This issue affects the function ext4_dirty_journalled_data of the component ext4. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ext4: only dirty folios when data journaling regular files fstest generic/388 occasionally reproduces a crash that looks as follows: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> ext4_block_zero_page_range+0x30c/0x380 [ext4] ext4_truncate+0x436/0x440 [ext4] ext4_process_orphan+0x5d/0x110 [ext4] ext4_orphan_cleanup+0x124/0x4f0 [ext4] ext4_fill_super+0x262d/0x3110 [ext4] get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x26/0xd0 vfs_cmd_create+0x59/0xe0 __do_sys_fsconfig+0x4ed/0x6b0 do_syscall_64+0x82/0x170 ... This occurs when processing a symlink inode from the orphan list. The partial block zeroing code in the truncate path calls ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an a_ops vector in ext4, hence the crash. To avoid this problem, update the ext4_dirty_journalled_data() helper to only mark the folio dirty on regular files (for which a_ops is assigned). This also matches the journaling logic in the ext4_symlink() creation path, where ext4_handle_dirty_metadata() is called directly.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-38220 since 04/16/2025. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 253428 (SUSE SLES15 Security Update : kernel (SUSE-SU-2025:02923-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.95, 6.12.35, 6.15.4 or 6.16-rc1 eliminates this vulnerability. Applying the patch cf6a4c4ac7b6e3214f25df594c9689a62f1bb456/be5f3061a6f904e3674257879e71881ceee5b673/d7af6eee8cd60f55aa8c5fe2b91f11ec0c9a0f27/e26268ff1dcae5662c1b96c35f18cfa6ab73d9de is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (253428), EUVD (EUVD-2025-20036) and CERT Bund (WID-SEC-2025-1465). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM QRadar SIEM
  • SUSE openSUSE
  • RESF Rocky Linux
  • Dell Avamar
  • Open Source Linux Kernel
  • Dell NetWorker
  • Dell Secure Connect Gateway

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 253428
Nessus Name: SUSE SLES15 Security Update : kernel (SUSE-SU-2025:02923-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.95/6.12.35/6.15.4/6.16-rc1
Patch: cf6a4c4ac7b6e3214f25df594c9689a62f1bb456/be5f3061a6f904e3674257879e71881ceee5b673/d7af6eee8cd60f55aa8c5fe2b91f11ec0c9a0f27/e26268ff1dcae5662c1b96c35f18cfa6ab73d9de

Timelineinfo

04/16/2025 CVE reserved
07/04/2025 +79 days Advisory disclosed
07/04/2025 +0 days VulDB entry created
12/13/2025 +162 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-38220 (🔒)
GCVE (CVE): GCVE-0-2025-38220
GCVE (VulDB): GCVE-100-314957
EUVD: 🔒
CERT Bund: WID-SEC-2025-1465 - Linux Kernel: Mehrere Schwachstellen erm&ouml;glichen Denial of Service

Entryinfo

Created: 07/04/2025 16:30
Updated: 12/13/2025 23:12
Changes: 07/04/2025 16:30 (59), 07/04/2025 17:59 (1), 07/20/2025 19:16 (7), 08/21/2025 21:50 (2), 08/25/2025 19:01 (1), 09/11/2025 09:21 (1), 09/21/2025 06:22 (1), 11/03/2025 04:03 (1), 11/18/2025 16:30 (13), 12/13/2025 23:12 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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