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NVD / CVE Program· CNA Linux

CVE-2021-47458: ocfs2: mount fails with buffer overflow in strlen

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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 0e677ea5b7396f715a76b6b0ef441430e4c4b57f, 232ed9752510de4436468b653d145565669c8498, 4b74ddcc22ee6455946e80a9c4808801f8f8561e.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0e677ea5b7396f715a76b6b0ef441430e4c4b57f, 232ed9752510de4436468b653d145565669c8498, 4b74ddcc22ee6455946e80a9c4808801f8f8561e 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: ocfs2: mount fails with buffer overflow in strlen Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the trace below. Problem seems to be that strings for cluster stack and cluster name are not guaranteed to be null terminated in the disk representation, while strlcpy assumes that the source string is always null terminated. This causes a read outside of the source string triggering the buffer overflow detection. detected buffer overflow in strlen ------------[ cut here ]------------ kernel BUG at lib/string.c:1149! invalid opcode: 0000 [#1] SMP PTI CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1 Debian 5.14.6-2 RIP: 0010:fortify_panic+0xf/0x11 ... Call Trace: ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2] ocfs2_fill_super+0x359/0x19b0 [ocfs2] mount_bdev+0x185/0x1b0 legacy_get_tree+0x27/0x40 vfs_get_tree+0x25/0xb0 path_mount+0x454/0xa20 __x64_sys_mount+0x103/0x140 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
May 22, 2024
Updated
Aug 5, 2026
EPSS
0.2% · 16th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 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
7.8
CNA · Linux
7.1
0.7 point gap

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

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

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.

Follow CVE-2021-47458

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 4.4.290
  • linux linux kernel4.5 and later · before 4.9.288
  • linux linux kernel4.10 and later · before 4.14.253
  • linux linux kernel4.15 and later · before 4.19.214
  • linux linux kernel4.20 and later · before 5.4.156
  • linux linux kernel5.5 and later · before 5.10.76
  • linux linux kernel5.11 and later · before 5.14.15
  • linux linux kernel5.15

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

    • 3.14affected
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before ac011cb3ff7a76b3e0e6e77158ee4ba2f929e1fbaffected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before 4b74ddcc22ee6455946e80a9c4808801f8f8561eaffected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before 232ed9752510de4436468b653d145565669c8498affected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before 7623b1035ca2d17bde0f6a086ad6844a34648df1affected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before d3a83576378b4c904f711598dde2c5e881c4295caffected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before 93be0eeea14cf39235e585c8f56df3b3859deaadaffected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before 0e677ea5b7396f715a76b6b0ef441430e4c4b57faffected · git
    • c74a3bdd9b529d924d1abf986079b783dd105ace and later · before b15fa9224e6e1239414525d8d556d824701849fcaffected · git
    • before 3.14not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.16-15.14.16-1

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-2021-47456May 22, 2024 · can: peak_pci: peak_pci_remove(): fix UAF
    33Monitor
  • ← EarlierCVE-2021-47457May 22, 2024 · can: isotp: isotp_sendmsg(): add result check for wait_event_interruptible()
    22Monitor
  • Later →CVE-2021-47459May 22, 2024 · can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
    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 Linux0e677ea5b7396f715a76b6b0ef441430e4c4b57fVendor (CNA)
Linux Linux232ed9752510de4436468b653d145565669c8498Vendor (CNA)
Linux Linux4b74ddcc22ee6455946e80a9c4808801f8f8561eVendor (CNA)
Linux Linux7623b1035ca2d17bde0f6a086ad6844a34648df1Vendor (CNA)
Linux Linux93be0eeea14cf39235e585c8f56df3b3859deaadVendor (CNA)
Linux Linuxac011cb3ff7a76b3e0e6e77158ee4ba2f929e1fbVendor (CNA)
Linux Linuxb15fa9224e6e1239414525d8d556d824701849fcVendor (CNA)
Linux Linuxd3a83576378b4c904f711598dde2c5e881c4295cVendor (CNA)
debian:linux5.14.16-1 · 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).

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
high · data can be read
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
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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