NVD / CVE Program· CNA Linux

CVE-2026-46124: isofs: validate block number from NFS file handle in isofs_export_iget

Noroxi assessment

Priority: Monitor (action score 30/100)

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: 0.47% (FIRST EPSS).
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.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: Linux Linux 0a1af74ae2177bda3aee0837a0546309aa539d0d, 24376458138387fb251e782e624c7776e9826796, 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0a1af74ae2177bda3aee0837a0546309aa539d0d, 24376458138387fb251e782e624c7776e9826796, 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5; azl3 kernel 6.6.139.1-1 on Azure Linux 3.0 6.6.141.1-1 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: validate block number from NFS file handle in isofs_export_iget isofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker- controlled block number (ifid->block or ifid->parent_block) from the NFS file handle to isofs_export_iget(), which only rejects block == 0 before calling isofs_iget() and ultimately sb_bread(). A crafted file handle with fh_len sufficient to pass the check added by commit 0405d4b63d08 ("isofs: Prevent the use of too small fid") can still drive the server to read any in-range block on the backing device as if it were an iso_directory_record. That earlier fix was assigned CVE-2025-37780. sb_bread() on an out-of-range block returns NULL cleanly via the EIO path, so there is no memory-safety violation. For in-range reads of adjacent-partition data on the same block device, the unrelated bytes end up in iso_inode_info fields that reach the NFS client as dentry metadata. The deployment surface (isofs exported over NFS from loop-mounted images) is narrow and requires an authenticated NFS peer, but the malformed-file-handle class is reportable as hardening next to the existing CVE-2025-37780 fix. Reject block >= ISOFS_SB(sb)->s_nzones in isofs_export_iget() so the check covers both isofs_fh_to_dentry() and isofs_fh_to_parent() call sites with a single line.

HighCVSS 7.5 · v3.1—No exploit Fix available

Published: May 28, 2026
Updated: Oct 19, 2026
EPSS: 0.4% · 40th percentile
CWE: CWE-125

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Linux: 7.5; 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

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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 kernel5.4.293 and later · before 5.5
linux linux kernel5.10.237 and later · before 5.10.258
linux linux kernel5.15.181 and later · before 5.15.209
linux linux kernel6.1.135 and later · before 6.1.175
linux linux kernel6.6.88 and later · before 6.6.140
linux linux kernel6.12.25 and later · before 6.12.88
linux linux kernel6.14.4 and later · before 6.15
linux linux kernel6.15.1 and later · before 6.18.30
linux linux kernel6.19 and later · before 7.0.7
linux linux kernel6.15
linux linux kernel7.1

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
- ee01a309ebf598be1ff8174901ed6e91619f1749, 007124c896e7d4614ac1f6bd4dedb975c35a2a8e, 6.15affected
- 5e7de55602c61c8ff28db075cc49c8dd6989d7e0 and later · before ee0024f5a7e3c73aa253869fae9650ae054093caaffected · git
- 63d5a3e207bf315a32c7d16de6c89753a759f95a and later · before 31dbb4ba0f719ae7774e4c0c95172c9bf81692f5affected · git
- 0fdafdaef796816a9ed0fd7ac812932d569d9beb and later · before 908a76f0b1038035e6ebb4f2293ce079f92e0a02affected · git
- 952e7a7e317f126d0a2b879fc531b716932d5ffa and later · before bb0988ed4f2e26d59bbb58f644cb3a55b7521e21affected · git
- 56dfffea9fd3be0b3795a9ca6401e133a8427e0b and later · before 0a1af74ae2177bda3aee0837a0546309aa539d0daffected · git
- 0405d4b63d082861f4eaff9d39c78ee9dc34f845 and later · before afbafeddf23db13fe2edb2d5c0bf4bbb13d7881baffected · git
- 0405d4b63d082861f4eaff9d39c78ee9dc34f845 and later · before 4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6affected · git
- 0405d4b63d082861f4eaff9d39c78ee9dc34f845 and later · before 24376458138387fb251e782e624c7776e9826796affected · git
- 5.10.237 and later · before 5.10.258affected · semver

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 6.1.176-1	6.1.176-1
Debian:13	linux	before 6.12.88-1	6.12.88-1
Debian:14	linux	before 7.0.7-1	7.0.7-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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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-2026-46120May 28, 2026 · ip6_gre: Use cached t->net in ip6erspan_changelink().
31Monitor
← EarlierCVE-2026-46122May 28, 2026 · wifi: b43: enforce bounds check on firmware key index in b43_rx()
31Monitor
Later →CVE-2026-46125May 28, 2026 · wifi: mac80211: remove station if connection prep fails
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 / package	Fixed version	Source
Linux Linux	0a1af74ae2177bda3aee0837a0546309aa539d0d	Vendor (CNA)
Linux Linux	24376458138387fb251e782e624c7776e9826796	Vendor (CNA)
Linux Linux	31dbb4ba0f719ae7774e4c0c95172c9bf81692f5	Vendor (CNA)
Linux Linux	4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6	Vendor (CNA)
Linux Linux	5.10.258	Vendor (CNA)
Linux Linux	5.15.209	Vendor (CNA)
Linux Linux	5.5	Vendor (CNA)
Linux Linux	6.1.175	Vendor (CNA)
Linux Linux	6.12.88	Vendor (CNA)
Linux Linux	6.15	Vendor (CNA)
Linux Linux	6.6.140	Vendor (CNA)
Linux Linux	908a76f0b1038035e6ebb4f2293ce079f92e0a02	Vendor (CNA)
Linux Linux	afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b	Vendor (CNA)
Linux Linux	bb0988ed4f2e26d59bbb58f644cb3a55b7521e21	Vendor (CNA)
Linux Linux	ee0024f5a7e3c73aa253869fae9650ae054093ca	Vendor (CNA)
azl3 kernel 6.6.139.1-1 on Azure Linux 3.0	6.6.141.1-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.176-1 · 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.

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.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).