NVD / CVE Program· CNA Linux

CVE-2021-47478: isofs: Fix out of bound access for corrupted isofs image

Noroxi assessment

Priority: Monitor (action score 36/100)

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: 0.68% (FIRST EPSS); higher than 52.9% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 156ce5bb6cc43a80a743810199defb1dc3f55b7f, 6e80e9314f8bb52d9eabe1907698718ff01120f5, 86d4aedcbc69c0f84551fb70f953c24e396de2d7.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 156ce5bb6cc43a80a743810199defb1dc3f55b7f, 6e80e9314f8bb52d9eabe1907698718ff01120f5, 86d4aedcbc69c0f84551fb70f953c24e396de2d7 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: isofs: Fix out of bound access for corrupted isofs image When isofs image is suitably corrupted isofs_read_inode() can read data beyond the end of buffer. Sanity-check the directory entry length before using it.

CriticalCVSS 9.1 · v3.1—No exploit Fix available

BDU:2024-10397

Published: May 22, 2024
Updated: Aug 5, 2026
EPSS: 0.6% · 52th percentile
CWE: CWE-125

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 36 / 40 · 9.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.6%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 9.1; 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.

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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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_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 4.4.292
linux linux kernel4.5 and later · before 4.9.290
linux linux kernel4.10 and later · before 4.14.255
linux linux kernel4.15 and later · before 4.19.217
linux linux kernel4.20 and later · before 5.4.159
linux linux kernel5.5 and later · before 5.10.79
linux linux kernel5.11 and later · before 5.14.18
linux linux kernel5.15 and later · before 5.15.2

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
- 2.6.12affected
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 156ce5bb6cc43a80a743810199defb1dc3f55b7faffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9ec33a9b8790c212cc926a88c5e2105f97f3f57eaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before afbd40f425227e661d991757e11cc4db024e761faffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b0ddff8d68f2e43857a84dce54c3deab181c8ae1affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6e80e9314f8bb52d9eabe1907698718ff01120f5affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 86d4aedcbc69c0f84551fb70f953c24e396de2d7affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before b2fa1f52d22c5455217b294629346ad23a744945affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e7fb722586a2936b37bdff096c095c30ca06404daffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e96a1866b40570b5950cda8602c2819189c62a48affected · git

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 5.15.3-1	5.15.3-1

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-2021-47476May 22, 2024 · comedi: ni_usb6501: fix NULL-deref in command paths
18Monitor
← EarlierCVE-2021-47477May 22, 2024 · comedi: dt9812: fix DMA buffers on stack
31Monitor
Later →CVE-2021-47479May 22, 2024 · staging: rtl8712: fix use-after-free in rtl8712_dl_fw
28Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Linux Linux	156ce5bb6cc43a80a743810199defb1dc3f55b7f	Vendor (CNA)
Linux Linux	6e80e9314f8bb52d9eabe1907698718ff01120f5	Vendor (CNA)
Linux Linux	86d4aedcbc69c0f84551fb70f953c24e396de2d7	Vendor (CNA)
Linux Linux	9ec33a9b8790c212cc926a88c5e2105f97f3f57e	Vendor (CNA)
Linux Linux	afbd40f425227e661d991757e11cc4db024e761f	Vendor (CNA)
Linux Linux	b0ddff8d68f2e43857a84dce54c3deab181c8ae1	Vendor (CNA)
Linux Linux	b2fa1f52d22c5455217b294629346ad23a744945	Vendor (CNA)
Linux Linux	e7fb722586a2936b37bdff096c095c30ca06404d	Vendor (CNA)
Linux Linux	e96a1866b40570b5950cda8602c2819189c62a48	Vendor (CNA)
debian:linux	5.15.3-1 · Debian:12	Package 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).