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NVD / CVE Program· CNA Linux

CVE-2021-46989: hfsplus: prevent corruption in shrinking truncate

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.24% (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 52dde855663e5db824af51db39b5757d2ef3e28a, 97314e45aa1223a42d60256a62c5d9af54baf446, adbd8a2a8cc05d9e501f93e5c95c59307874cc99.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 52dde855663e5db824af51db39b5757d2ef3e28a, 97314e45aa1223a42d60256a62c5d9af54baf446, adbd8a2a8cc05d9e501f93e5c95c59307874cc99 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: hfsplus: prevent corruption in shrinking truncate I believe there are some issues introduced by commit 31651c607151 ("hfsplus: avoid deadlock on file truncation") HFS+ has extent records which always contains 8 extents. In case the first extent record in catalog file gets full, new ones are allocated from extents overflow file. In case shrinking truncate happens to middle of an extent record which locates in extents overflow file, the logic in hfsplus_file_truncate() was changed so that call to hfs_brec_remove() is not guarded any more. Right action would be just freeing the extents that exceed the new size inside extent record by calling hfsplus_free_extents(), and then check if the whole extent record should be removed. However since the guard (blk_cnt > start) is now after the call to hfs_brec_remove(), this has unfortunate effect that the last matching extent record is removed unconditionally. To reproduce this issue, create a file which has at least 10 extents, and then perform shrinking truncate into middle of the last extent record, so that the number of remaining extents is not under or divisible by 8. This causes the last extent record (8 extents) to be removed totally instead of truncating into middle of it. Thus this causes corruption, and lost data. Fix for this is simply checking if the new truncated end is below the start of this extent record, making it safe to remove the full extent record. However call to hfs_brec_remove() can't be moved to it's previous place since we're dropping ->tree_lock and it can cause a race condition and the cached info being invalidated possibly corrupting the node data. Another issue is related to this one. When entering into the block (blk_cnt > start) we are not holding the ->tree_lock. We break out from the loop not holding the lock, but hfs_find_exit() does unlock it. Not sure if it's possible for someone else to take the lock under our feet, but it can cause hard to debug errors and premature unlocking. Even if there's no real risk of it, the locking should still always be kept in balance. Thus taking the lock now just before the check.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Feb 28, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 15th percentile
CWE
—

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 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.

CNA vs NVD score

NVD
—
CNA · Linux
7.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
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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 kernel4.19 and later · before 4.19.191
  • linux linux kernel4.20 and later · before 5.4.120
  • linux linux kernel5.5 and later · before 5.10.38
  • linux linux kernel5.11 and later · before 5.11.22
  • linux linux kernel5.12 and later · before 5.12.5
  • linux linux kernel5.13

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

    • 4.19affected
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before 52dde855663e5db824af51db39b5757d2ef3e28aaffected · git
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before c451a6bafb5f422197d31536f82116aed132b72caffected · git
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before adbd8a2a8cc05d9e501f93e5c95c59307874cc99affected · git
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before c477f62db1a0c0ecaa60a29713006ceeeb04b685affected · git
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before 97314e45aa1223a42d60256a62c5d9af54baf446affected · git
    • 31651c607151f1034cfb57e5a78678bea54c362b and later · before c3187cf32216313fb316084efac4dab3a8459b1daffected · git
    • before 4.19not affected · semver
    • 4.19.191 and later · up to and including 4.19.*not affected · semver
    • 5.4.120 and later · up to and including 5.4.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.10.38-15.10.38-1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-default-basebefore 5.3.18-150200.24.183.1.150200.9.93.25.3.18-150200.24.183.1.150200.9.93.2
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-docsbefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-obs-buildbefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-preemptbefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-sourcebefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSSkernel-symsbefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-64kbbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-default-basebefore 5.3.18-150300.59.153.2.150300.18.90.25.3.18-150300.59.153.2.150300.18.90.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-docsbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-obs-buildbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-preemptbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-sourcebefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-symsbefore 5.3.18-150300.59.153.15.3.18-150300.59.153.1
SUSE:Linux Enterprise Live Patching 15 SP2kernel-defaultbefore 5.3.18-150200.24.183.15.3.18-150200.24.183.1
SUSE:Linux Enterprise Live Patching 15 SP2kernel-livepatch-SLE15-SP2_Update_46before 1-150200.5.3.21-150200.5.3.2
SUSE:Linux Enterprise Live Patching 15 SP3kernel-defaultbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2
SUSE:Linux Enterprise Live Patching 15 SP3kernel-livepatch-SLE15-SP3_Update_42before 1-150300.7.3.21-150300.7.3.2
SUSE:Linux Enterprise Micro 5.1kernel-rtbefore 5.3.18-150300.161.15.3.18-150300.161.1
SUSE:Linux Enterprise Micro 5.1kernel-source-rtbefore 5.3.18-150300.161.15.3.18-150300.161.1
SUSE:Linux Enterprise Server 15 SP3-LTSSkernel-zfcpdumpbefore 5.3.18-150300.59.153.25.3.18-150300.59.153.2

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-2021-46987Feb 28, 2024 · btrfs: fix deadlock when cloning inline extents and using qgroups
    22Monitor
  • ← EarlierCVE-2021-46988Feb 28, 2024 · userfaultfd: release page in error path to avoid BUG_ON
    22Monitor
  • Later →CVE-2021-46990Feb 28, 2024 · powerpc/64s: Fix crashes when toggling entry flush barrier
    22Monitor

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 Linux52dde855663e5db824af51db39b5757d2ef3e28aVendor (CNA)
Linux Linux97314e45aa1223a42d60256a62c5d9af54baf446Vendor (CNA)
Linux Linuxadbd8a2a8cc05d9e501f93e5c95c59307874cc99Vendor (CNA)
Linux Linuxc3187cf32216313fb316084efac4dab3a8459b1dVendor (CNA)
Linux Linuxc451a6bafb5f422197d31536f82116aed132b72cVendor (CNA)
Linux Linuxc477f62db1a0c0ecaa60a29713006ceeeb04b685Vendor (CNA)
debian:linux5.10.38-1 · Debian:12Package registry (OSV)
suse:kernel-64kb5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-default5.3.18-150300.59.153.2 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-default-base5.3.18-150300.59.153.2.150300.18.90.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-docs5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP3_Update_421-150300.7.3.2 · SUSE:Linux Enterprise Live Patching 15 SP3Package registry (OSV)
suse:kernel-obs-build5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-preempt5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-rt5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-source5.3.18-150300.59.153.2 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-source-rt5.3.18-150300.161.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:kernel-syms5.3.18-150300.59.153.1 · SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSPackage registry (OSV)
suse:kernel-zfcpdump5.3.18-150300.59.153.2 · SUSE:Linux Enterprise Server 15 SP3-LTSSPackage 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
high · data or configuration can be modified
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
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

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 (5 more)

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

All records