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NVD / CVE Program· CNA Linux

CVE-2026-53320: nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()

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: 0.17% (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 4525658002be3ad310b16bf8db48c8adb6a55d32, 65e07964b4b2daf9a54e686cf0fa72d74a9648a8, 94094e70fe292c9566502772d4d4d6d6a99204b1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 4525658002be3ad310b16bf8db48c8adb6a55d32, 65e07964b4b2daf9a54e686cf0fa72d74a9648a8, 94094e70fe292c9566502772d4d4d6d6a99204b1 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

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty() nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks by comparing it with the current block number bd_blocknr. If they differ, the block is considered dead and skipped. However, bd_oblocknr should never be 0 since block 0 typically stores the primary superblock and is never a valid GC target block. A corrupted ioctl request with bd_oblocknr set to 0 causes the comparison to incorrectly match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering the WARN_ON(ret == -ENOENT). Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the beginning of each iteration. [ryusuke: slightly modified the commit message and comments for accuracy]

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 26, 2026
Updated
Jul 6, 2026
EPSS
0.1% · 6th percentile
CWE
—

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 · 0.1%

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

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  • when exploit code appears or is weaponized
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  • 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 kernel2.6.30 and later · before 5.10.258
  • linux linux kernel5.11 and later · before 5.15.209
  • linux linux kernel5.16 and later · before 6.1.175
  • linux linux kernel6.2 and later · before 6.6.141
  • linux linux kernel6.7 and later · before 6.12.91
  • linux linux kernel6.13 and later · before 6.18.33
  • linux linux kernel6.19 and later · before 7.0.10

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

    • 2.6.30affected
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before e0a0c4903cbba351f0f5b5d104960d3a5b23202faffected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before 9472d37799a0b9ff9b99639f35961ac2f0b3c9beaffected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before 65e07964b4b2daf9a54e686cf0fa72d74a9648a8affected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before b88f905d4449b70da6bda547be546e365e44352eaffected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before 4525658002be3ad310b16bf8db48c8adb6a55d32affected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before e5ff0ba4b6983cdbcc826efc201e7179ece5d46faffected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before 94094e70fe292c9566502772d4d4d6d6a99204b1affected · git
    • 7942b919f7321f95a777d396ff7894a7a83dc9b0 and later · before be3e5d10643d3be1cbac9d9939f220a99253f980affected · git
    • before 2.6.30not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.176-16.1.176-1
Debian:13linuxbefore 6.12.94-16.12.94-1
Debian:14linuxbefore 7.0.10-17.0.10-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • 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

Published before and after this one in the same product

  • ← EarlierCVE-2026-53318Jun 26, 2026 · wifi: mt76: mt7925: prevent NULL pointer dereference in mt7925_tx_check_aggr()
    22Monitor
  • ← EarlierCVE-2026-53319Jun 26, 2026 · blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()
    22Monitor
  • Later →CVE-2026-53322Jun 26, 2026 · vfio/pci: Clean up DMABUFs before disabling function
    35Monitor

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 Linux4525658002be3ad310b16bf8db48c8adb6a55d32Vendor (CNA)
Linux Linux65e07964b4b2daf9a54e686cf0fa72d74a9648a8Vendor (CNA)
Linux Linux94094e70fe292c9566502772d4d4d6d6a99204b1Vendor (CNA)
Linux Linux9472d37799a0b9ff9b99639f35961ac2f0b3c9beVendor (CNA)
Linux Linuxb88f905d4449b70da6bda547be546e365e44352eVendor (CNA)
Linux Linuxbe3e5d10643d3be1cbac9d9939f220a99253f980Vendor (CNA)
Linux Linuxe0a0c4903cbba351f0f5b5d104960d3a5b23202fVendor (CNA)
Linux Linuxe5ff0ba4b6983cdbcc826efc201e7179ece5d46fVendor (CNA)
debian:linux6.1.176-1 · 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.

No history yet (it accumulates with the daily EPSS job).

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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)

—

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 (7 more)

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

All records