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CVE-2022-50344· NVD / CVE Program· CNA Linux

ext4: fix null-ptr-deref in ext4_write_info

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4, 4a657319cfabd6199fd0b7b65bbebf6ded7a11c1, 533c60a0b97cee5daab376933f486207e6680fb7.

Low priority for now. Upgrade to Linux Linux 3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4, 4a657319cfabd6199fd0b7b65bbebf6ded7a11c1, 533c60a0b97cee5daab376933f486207e6680fb7 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

In the Linux kernel, the following vulnerability has been resolved: ext4: fix null-ptr-deref in ext4_write_info I caught a null-ptr-deref bug as follows: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339 RIP: 0010:ext4_write_info+0x53/0x1b0 [...] Call Trace: dquot_writeback_dquots+0x341/0x9a0 ext4_sync_fs+0x19e/0x800 __sync_filesystem+0x83/0x100 sync_filesystem+0x89/0xf0 generic_shutdown_super+0x79/0x3e0 kill_block_super+0xa1/0x110 deactivate_locked_super+0xac/0x130 deactivate_super+0xb6/0xd0 cleanup_mnt+0x289/0x400 __cleanup_mnt+0x16/0x20 task_work_run+0x11c/0x1c0 exit_to_user_mode_prepare+0x203/0x210 syscall_exit_to_user_mode+0x5b/0x3a0 do_syscall_64+0x59/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ================================================================== Above issue may happen as follows: ------------------------------------- exit_to_user_mode_prepare task_work_run __cleanup_mnt cleanup_mnt deactivate_super deactivate_locked_super kill_block_super generic_shutdown_super shrink_dcache_for_umount dentry = sb->s_root sb->s_root = NULL <--- Here set NULL sync_filesystem __sync_filesystem sb->s_op->sync_fs > ext4_sync_fs dquot_writeback_dquots sb->dq_op->write_info > ext4_write_info ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2) d_inode(sb->s_root) s_root->d_inode <--- Null pointer dereference To solve this problem, we use ext4_journal_start_sb directly to avoid s_root being used.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 16, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 5th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernelbefore 4.9.331
  • linux linux kernel4.10 and later · before 4.14.296
  • linux linux kernel4.15 and later · before 4.19.262
  • linux linux kernel4.20 and later · before 5.4.220
  • linux linux kernel5.5 and later · before 5.10.150
  • linux linux kernel5.11 and later · before 5.15.75
  • linux linux kernel5.16 and later · before 5.19.17
  • linux linux kernel6.0 and later · before 6.0.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.6affected
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before dc451578446afd03c0c21913993c08898a691435affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before f4b5ff0b794aa94afac7269c494550ca2f66511baffected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before 947264e00c46de19a016fd81218118c708fed2f3affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before 3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before f34ab95162763cd7352f46df169296eec28b688daffected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before 533c60a0b97cee5daab376933f486207e6680fb7affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before 4a657319cfabd6199fd0b7b65bbebf6ded7a11c1affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before bb420e8afc854d2a1caaa23a0c129839acfb7888affected · git
    • a1177825719ccef3f76ef39bbfd5ebb6087d53c7 and later · before f9c1f248607d5546075d3f731e7607d5571f2b60affected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.0.3-16.0.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now
  • CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV
    77This week
  • CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV
    77This week
  • CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV
    77This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4Vendor (CNA)
Linux Linux4a657319cfabd6199fd0b7b65bbebf6ded7a11c1Vendor (CNA)
Linux Linux533c60a0b97cee5daab376933f486207e6680fb7Vendor (CNA)
Linux Linux947264e00c46de19a016fd81218118c708fed2f3Vendor (CNA)
Linux Linuxbb420e8afc854d2a1caaa23a0c129839acfb7888Vendor (CNA)
Linux Linuxdc451578446afd03c0c21913993c08898a691435Vendor (CNA)
Linux Linuxf34ab95162763cd7352f46df169296eec28b688dVendor (CNA)
Linux Linuxf4b5ff0b794aa94afac7269c494550ca2f66511bVendor (CNA)
Linux Linuxf9c1f248607d5546075d3f731e7607d5571f2b60Vendor (CNA)
debian:linux6.0.3-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records