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NVD / CVE Program· CNA Linux

CVE-2021-47117: ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed

MediumCVSS 5.5 · v3.1—No exploit Fix available

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: 0.24% (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 082cd4ec240b8734a82a89ffb890216ac98fec68, 48105dc98c9ca35af418746277b087cb2bc6df7c, 569496aa3776eea1ff0d49d0174ac1b7e861e107.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 082cd4ec240b8734a82a89ffb890216ac98fec68, 48105dc98c9ca35af418746277b087cb2bc6df7c, 569496aa3776eea1ff0d49d0174ac1b7e861e107 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: ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed We got follow bug_on when run fsstress with injecting IO fault: [130747.323114] kernel BUG at fs/ext4/extents_status.c:762! [130747.323117] Internal error: Oops - BUG: 0 [#1] SMP ...... [130747.334329] Call trace: [130747.334553] ext4_es_cache_extent+0x150/0x168 [ext4] [130747.334975] ext4_cache_extents+0x64/0xe8 [ext4] [130747.335368] ext4_find_extent+0x300/0x330 [ext4] [130747.335759] ext4_ext_map_blocks+0x74/0x1178 [ext4] [130747.336179] ext4_map_blocks+0x2f4/0x5f0 [ext4] [130747.336567] ext4_mpage_readpages+0x4a8/0x7a8 [ext4] [130747.336995] ext4_readpage+0x54/0x100 [ext4] [130747.337359] generic_file_buffered_read+0x410/0xae8 [130747.337767] generic_file_read_iter+0x114/0x190 [130747.338152] ext4_file_read_iter+0x5c/0x140 [ext4] [130747.338556] __vfs_read+0x11c/0x188 [130747.338851] vfs_read+0x94/0x150 [130747.339110] ksys_read+0x74/0xf0 This patch's modification is according to Jan Kara's suggestion in: https://patchwork.ozlabs.org/project/linux-ext4/patch/20210428085158.3728201-1-yebin10@huawei.com/ "I see. Now I understand your patch. Honestly, seeing how fragile is trying to fix extent tree after split has failed in the middle, I would probably go even further and make sure we fix the tree properly in case of ENOSPC and EDQUOT (those are easily user triggerable). Anything else indicates a HW problem or fs corruption so I'd rather leave the extent tree as is and don't try to fix it (which also means we will not create overlapping extents)."

Published
Mar 15, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th 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 · 0.2%

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

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Follow CVE-2021-47117

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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

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

    • 3.9affected
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before e33bafad30d34cfa5e9787cb099cab05e2677fcbaffected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before 5b3a9a2be59478b013a430ac57b0f3d65471b071affected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before d8116743ef5432336289256b2f7c117299213eb9affected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before 569496aa3776eea1ff0d49d0174ac1b7e861e107affected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before 920697b004e49cb026e2e15fe91be065bf0741b7affected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before d3b668b96ad3192c0581a248ae2f596cd054792aaffected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before 48105dc98c9ca35af418746277b087cb2bc6df7caffected · git
    • adb2355104b2109e06ba5276485d187d023b2fd2 and later · before 082cd4ec240b8734a82a89ffb890216ac98fec68affected · git
    • before 3.9not affected · semver
Affected versions · NVD (8)

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

  • linux linux kernelbefore 4.4.272
  • linux linux kernel4.5 and later · before 4.9.272
  • linux linux kernel4.10 and later · before 4.14.236
  • linux linux kernel4.15 and later · before 4.19.194
  • linux linux kernel4.20 and later · before 5.4.125
  • linux linux kernel5.5 and later · before 5.10.43
  • linux linux kernel5.11 and later · before 5.12.10
  • linux linux kernel5.13

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.10.46-15.10.46-1

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-2021-47114Mar 15, 2024 · ocfs2: fix data corruption by fallocate
    22Monitor
  • ← EarlierCVE-2021-47116Mar 15, 2024 · ext4: fix memory leak in ext4_mb_init_backend on error path.
    22Monitor
  • Later →CVE-2021-47118Mar 15, 2024 · pid: take a reference when initializing `cad_pid`
    31Monitor

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 Linux082cd4ec240b8734a82a89ffb890216ac98fec68Vendor (CNA)
Linux Linux48105dc98c9ca35af418746277b087cb2bc6df7cVendor (CNA)
Linux Linux569496aa3776eea1ff0d49d0174ac1b7e861e107Vendor (CNA)
Linux Linux5b3a9a2be59478b013a430ac57b0f3d65471b071Vendor (CNA)
Linux Linux920697b004e49cb026e2e15fe91be065bf0741b7Vendor (CNA)
Linux Linuxd3b668b96ad3192c0581a248ae2f596cd054792aVendor (CNA)
Linux Linuxd8116743ef5432336289256b2f7c117299213eb9Vendor (CNA)
Linux Linuxe33bafad30d34cfa5e9787cb099cab05e2677fcbVendor (CNA)
debian:linux5.10.46-1 · 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.

National notice (Türkiye Cybersecurity Directorate / USOM)

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

All national notices →

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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.

References

Show all references (7 more)

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

All records