CVE-2026-31447: ext4: reject mount if bigalloc with s_first_data_block != 0
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: 0.14% (FIRST EPSS).
- Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
- Fixed version: Linux Linux 3822743dc20386d9897e999dbb990befa3a5b3f8, 3a926957cc95899ef88529710836edadc03c71a1, 5ad6d994255e27a3254079dfb50ca861fc31f2d0; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2.
Low priority for now. Upgrade to Linux Linux 3822743dc20386d9897e999dbb990befa3a5b3f8, 3a926957cc95899ef88529710836edadc03c71a1, 5ad6d994255e27a3254079dfb50ca861fc31f2d0; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2 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: reject mount if bigalloc with s_first_data_block != 0 bigalloc with s_first_data_block != 0 is not supported, reject mounting it.
- Published
- Apr 22, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.1% · 3th percentile
- CWE
- CWE-20
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.8
- 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.
We use this product, ask for helpAffected 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 kernel3.2 and later · before 5.10.253
- linux linux kernel5.11 and later · before 5.15.203
- linux linux kernel5.16 and later · before 6.1.168
- linux linux kernel6.2 and later · before 6.6.131
- linux linux kernel6.7 and later · before 6.12.80
- linux linux kernel6.13 and later · before 6.18.21
- linux linux kernel6.19 and later · before 6.19.11
- linux linux kernel7.0
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
- 3.2affected
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before 5ad6d994255e27a3254079dfb50ca861fc31f2d0affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before 3a926957cc95899ef88529710836edadc03c71a1affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before 7b58c110b4e1f028eb38eec9ed3555e9be81c8b0affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before b77de3fceafbb39f30e4ff5dc986f863d5456417affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before d787d3ae96648dc14a3b7ca8fde817177e82c1c7affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before ad1f6d608f33f59d21a3d025615d6786a6443998affected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before 7d5b04290156c3fc316eecc86a4f9d201ab7d44aaffected · git
- 281b59959707dfae03ce038cdf231bf4904e170c and later · before 3822743dc20386d9897e999dbb990befa3a5b3f8affected · git
- before 3.2not affected · 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 6.1.170-1 | 6.1.170-1 |
| Debian:13 | linux | before 6.12.85-1 | 6.12.85-1 |
| Debian:14 | linux | before 6.19.11-1 | 6.19.11-1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kernel-default | before 4.12.14-122.317.1 | 4.12.14-122.317.1 |
| SUSE:Linux Enterprise Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_84 | before 1-8.7.1 | 1-8.7.1 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_19 | before 1-150700.15.3.4 | 1-150700.15.3.4 |
| SUSE:Linux Enterprise Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_18 | before 1-150700.1.5.1 | 1-150700.1.5.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-64kb | before 6.4.0-150700.53.73.2 | 6.4.0-150700.53.73.2 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-default | before 6.4.0-150700.53.73.2 | 6.4.0-150700.53.73.2 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-default-base | before 6.4.0-150700.53.73.2.150700.17.41.4 | 6.4.0-150700.53.73.2.150700.17.41.4 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-source | before 6.4.0-150700.53.73.1 | 6.4.0-150700.53.73.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | kernel-zfcpdump | before 6.4.0-150700.53.73.2 | 6.4.0-150700.53.73.2 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | kernel-docs | before 6.4.0-150700.53.73.1 | 6.4.0-150700.53.73.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | kernel-obs-build | before 6.4.0-150700.53.73.2 | 6.4.0-150700.53.73.2 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | kernel-syms | before 6.4.0-150700.53.73.1 | 6.4.0-150700.53.73.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP7 | kernel-azure | before 6.4.0-150700.53.73.2 | 6.4.0-150700.53.73.2 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | kernel-source | before 4.12.14-122.317.1 | 4.12.14-122.317.1 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | kernel-syms | before 4.12.14-122.317.1 | 4.12.14-122.317.1 |
| SUSE:Real Time Module 15 SP7 | kernel-rt | before 6.4.0-150700.7.67.1 | 6.4.0-150700.7.67.1 |
| SUSE:Real Time Module 15 SP7 | kernel-source-rt | before 6.4.0-150700.7.67.1 | 6.4.0-150700.7.67.1 |
| SUSE:Real Time Module 15 SP7 | kernel-syms-rt | before 6.4.0-150700.7.67.1 | 6.4.0-150700.7.67.1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV90Now
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
Published before and after this one in the same product
- ← EarlierCVE-2026-31442Apr 22, 2026 · dmaengine: idxd: Fix possible invalid memory access after FLR31Monitor
- ← EarlierCVE-2026-31446Apr 22, 2026 · ext4: fix use-after-free in update_super_work when racing with umount31Monitor
- Later →CVE-2026-31448Apr 22, 2026 · ext4: avoid infinite loops caused by residual data37Monitor
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 | 3822743dc20386d9897e999dbb990befa3a5b3f8 | Vendor (CNA) |
| Linux Linux | 3a926957cc95899ef88529710836edadc03c71a1 | Vendor (CNA) |
| Linux Linux | 5ad6d994255e27a3254079dfb50ca861fc31f2d0 | Vendor (CNA) |
| Linux Linux | 7b58c110b4e1f028eb38eec9ed3555e9be81c8b0 | Vendor (CNA) |
| Linux Linux | 7d5b04290156c3fc316eecc86a4f9d201ab7d44a | Vendor (CNA) |
| Linux Linux | ad1f6d608f33f59d21a3d025615d6786a6443998 | Vendor (CNA) |
| Linux Linux | b77de3fceafbb39f30e4ff5dc986f863d5456417 | Vendor (CNA) |
| Linux Linux | d787d3ae96648dc14a3b7ca8fde817177e82c1c7 | Vendor (CNA) |
| azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 | 6.6.134.1-2 · CBL-Mariner Releases | Microsoft (MSRC) |
| debian:linux | 6.1.170-1 · Debian:12 | Package registry (OSV) |
| suse:kernel-64kb | 6.4.0-150700.53.73.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | Package registry (OSV) |
| suse:kernel-default | 4.12.14-122.317.1 · SUSE:Linux Enterprise Live Patching 12 SP5 | Package registry (OSV) |
| suse:kernel-default-base | 6.4.0-150700.53.73.2.150700.17.41.4 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | Package registry (OSV) |
| suse:kernel-docs | 6.4.0-150700.53.73.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7 | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP7-RT_Update_18 | 1-150700.1.5.1 · SUSE:Linux Enterprise Live Patching 15 SP7 | Package registry (OSV) |
| suse:kernel-rt | 6.4.0-150700.7.67.1 · SUSE:Real Time Module 15 SP7 | Package registry (OSV) |
| suse:kernel-source | 4.12.14-122.317.1 · SUSE:Linux Enterprise Server 12 SP5-LTSS | Package registry (OSV) |
| suse:kernel-source-rt | 6.4.0-150700.7.67.1 · SUSE:Real Time Module 15 SP7 | Package registry (OSV) |
| suse:kernel-syms | 4.12.14-122.317.1 · SUSE:Linux Enterprise Server 12 SP5-LTSS | Package registry (OSV) |
| suse:kernel-syms-rt | 6.4.0-150700.7.67.1 · SUSE:Real Time Module 15 SP7 | Package registry (OSV) |
| suse:kernel-zfcpdump | 6.4.0-150700.53.73.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | Package registry (OSV) |
| suse:kgraft-patch-SLE12-SP5_Update_84 | 1-8.7.1 · SUSE:Linux Enterprise Live Patching 12 SP5 | 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 researchersFinders, 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.
- CVE-2026-4611536 days apartblock: add pgmap check to biovec_phys_mergeable39Monitor
- CVE-2026-5322164 days apartip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()39Monitor
- CVE-2026-6403788 days apartwifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled39Monitor
- CVE-2026-6404688 days apartnet: tls: prevent chain-after-chain in plain text SG39Monitor
- CVE-2026-4311414 days apartnetfilter: nft_set_pipapo_avx2: don't return non-matching entry on expiry37Monitor
- CVE-2026-4626642 days apartinet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP36Monitor
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).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (10 more)Show less
- git.kernel.org/stable/c/3a926957cc95899ef88529710836edadc03c71a1
- git.kernel.org/stable/c/5ad6d994255e27a3254079dfb50ca861fc31f2d0
- git.kernel.org/stable/c/7b58c110b4e1f028eb38eec9ed3555e9be81c8b0
- git.kernel.org/stable/c/7d5b04290156c3fc316eecc86a4f9d201ab7d44a
- git.kernel.org/stable/c/ad1f6d608f33f59d21a3d025615d6786a6443998
- git.kernel.org/stable/c/b77de3fceafbb39f30e4ff5dc986f863d5456417
- git.kernel.org/stable/c/d787d3ae96648dc14a3b7ca8fde817177e82c1c7
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.