CVE-2026-31452 — ext4: convert inline data to extents when truncate exceeds inline size
In the Linux kernel, the following vulnerability has been resolved: ext4: convert inline data to extents when truncate exceeds inline size Add a check in ext4_setattr() to convert files from inline data storage to extent-based storage when truncate() grows the file size beyond the inline capacity. This prevents the filesystem from entering an inconsistent state where the inline data flag is set but the file size exceeds what can be stored inline. Without this fix, the following sequence causes a kernel BUG_ON(): 1. Mount filesystem with inode that has inline flag set and small size 2. truncate(file, 50MB) - grows size but inline flag remains set 3. sendfile() attempts to write data 4. ext4_write_inline_data() hits BUG_ON(write_size > inline_capacity) The crash occurs because ext4_write_inline_data() expects inline storage to accommodate the write, but the actual inline capacity (~60 bytes for i_block + ~96 bytes for xattrs) is far smaller than the file size and write request. The fix checks if the new size from setattr exceeds the inode's actual inline capacity (EXT4_I(inode)->i_inline_size) and converts the file to extent-based storage before proceeding with the size change. This addresses the root cause by ensuring the inline data flag and file size remain consistent during truncate operations.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 3.8≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < ed9356a30e59c7cc3198e7fc46cfedf3767b9b17≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < 07c1a31af18290054da3d18221b8bf58983c5d3a≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < 93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < 7920dcc571cef3d8aa9ee109c136125d61d41669≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < 699bac4d4c951974d55b045c983d1de777215949≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < c047332be7195833a5c5126816c2502df8269fe4≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < f53a5d9f32924bc2a810d2df243b7714da58b636 and 1 more≥ 67cf5b09a46f72e048501b84996f2f77bc42e947 and < 110d7ef602659ce4d7947c5480f7ca2779696aaf |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 7.0-rc4version 7.0-rc5≥ 3.8 and < 5.10.253version 7.0-rc3version 7.0-rc2version 7.0-rc1≥ 6.19 and < 6.19.11≥ 6.13 and < 6.18.21 and 4 more≥ 6.7 and < 6.12.80≥ 6.2 and < 6.6.131≥ 5.16 and < 6.1.168≥ 5.11 and < 5.15.203 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.18%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Modified
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 14, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
13 on the record
- git.kernel.org/stable/c/110d7ef602659ce4d7947c5480f7ca2779696aaf
- git.kernel.org/stable/c/7920dcc571cef3d8aa9ee109c136125d61d41669
- git.kernel.org/stable/c/c047332be7195833a5c5126816c2502df8269fe4
- git.kernel.org/stable/c/699bac4d4c951974d55b045c983d1de777215949
- git.kernel.org/stable/c/ed9356a30e59c7cc3198e7fc46cfedf3767b9b17
- git.kernel.org/stable/c/93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6
- git.kernel.org/stable/c/f53a5d9f32924bc2a810d2df243b7714da58b636
- git.kernel.org/stable/c/07c1a31af18290054da3d18221b8bf58983c5d3a
- nvd.nist.gov/vuln/detail/CVE-2026-31452
- cert-portal.siemens.com/productcert/html/ssa-082556.html
- cert-portal.siemens.com/productcert/html/ssa-457936.html
- cert-portal.siemens.com/productcert/html/ssa-019113.html
- github.com/advisories/GHSA-g495-4jqx-cp59
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 8h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 8h
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CISA SSVC assessment.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-31452 is "ext4: convert inline data to extents when truncate exceeds inline size", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.