ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O
In the Linux kernel, the following vulnerability has been resolved: ext4: don't set EXT4_GET_BLOCKS_CONVERT when splitting before submitting I/O When allocating blocks during within-EOF DIO and writeback with dioread_nolock enabled, EXT4_GET_BLOCKS_PRE_IO was set to split an existing large unwritten extent. However, EXT4_GET_BLOCKS_CONVERT was set when calling ext4_split_convert_extents(), which may potentially result in stale data issues. Assume we have an unwritten extent, and then DIO writes the second half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, ext4_iomap_alloc() call ext4_map_blocks() with EXT4_GET_BLOCKS_PRE_IO, EXT4_GET_BLOCKS_UNWRIT_EXT and EXT4_GET_BLOCKS_CREATE flags set. ext4_map_blocks() find this extent and call ext4_split_convert_extents() with EXT4_GET_BLOCKS_CONVERT and the above flags set. Then, ext4_split_convert_extents() calls ext4_split_extent() with EXT4_EXT_MAY_ZEROOUT, EXT4_EXT_MARK_UNWRIT2 and EXT4_EXT_DATA_VALID2 flags set, and it calls ext4_split_extent_at() to split the second half with EXT4_EXT_DATA_VALID2, EXT4_EXT_MARK_UNWRIT1, EXT4_EXT_MAY_ZEROOUT and EXT4_EXT_MARK_UNWRIT2 flags set. However, ext4_split_extent_at() failed to insert extent since a temporary lack -ENOSPC. It zeroes out the first half but convert the entire on-disk extent to written since the EXT4_EXT_DATA_VALID2 flag set, but left the second half as unwritten in the extent status tree. [0000000000SSSSSS] data S: stale data, 0: zeroed [WWWWWWWWWWWWWWWW] on-disk extent W: written extent [WWWWWWWWWWUUUUUU] extent status tree Finally, if the DIO failed to write data to the disk, the stale data in the second half will be exposed once the cached extent entry is gone. Fix this issue by not passing EXT4_GET_BLOCKS_CONVERT when splitting an unwritten extent before submitting I/O, and make ext4_split_convert_extents() to zero out the entire extent range to zero for this case, and also mark the extent in the extent status tree for consistency.
- Published
- May 27, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 5th percentile
- CWE
- —
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Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
Noroxi analysis
No Noroxi analysis for this record yet
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We use this product, ask for helpAffected systems
| 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 kernel3.15 and later · before 5.10.253
- linux linux kernel5.11 and later · before 5.15.203
- linux linux kernel5.16 and later · before 6.6.130
- linux linux kernel6.7 and later · before 6.12.77
- linux linux kernel6.13 and later · before 6.18.17
- linux linux kernel6.19 and later · before 6.19.4
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
- 3.15affected
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 77e407967cd872cd75d7e4a691908e49c8e6b4d4affected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 37555690f39f78ef69af347d9aff897e07445949affected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 67cdb7bd7442bd3cdc6d6088bbb2df9be2fe936caffected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 2920ec61c98b9476781359f05b94da84e80f54d4affected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 2698731d25823267c29190cb578da9296a0c0d7baffected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before 716e7439a5a9b18c3ff882c2f8c834b9ced1aaecaffected · git
- b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 and later · before feaf2a80e78f89ee8a3464126077ba8683b62791affected · git
- before 3.15not affected · semver
- 5.10.253 and later · up to and including 5.10.*not 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 | all versions | — |
| Debian:13 | linux | before 6.12.85-1 | 6.12.85-1 |
| Debian:14 | linux | before 6.19.6-1 | 6.19.6-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
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- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This week
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 | 2698731d25823267c29190cb578da9296a0c0d7b | Vendor (CNA) |
| Linux Linux | 2920ec61c98b9476781359f05b94da84e80f54d4 | Vendor (CNA) |
| Linux Linux | 37555690f39f78ef69af347d9aff897e07445949 | Vendor (CNA) |
| Linux Linux | 67cdb7bd7442bd3cdc6d6088bbb2df9be2fe936c | Vendor (CNA) |
| Linux Linux | 716e7439a5a9b18c3ff882c2f8c834b9ced1aaec | Vendor (CNA) |
| Linux Linux | 77e407967cd872cd75d7e4a691908e49c8e6b4d4 | Vendor (CNA) |
| Linux Linux | feaf2a80e78f89ee8a3464126077ba8683b62791 | Vendor (CNA) |
| debian:linux | 6.12.85-1 · Debian:13 | 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.
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 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.
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.
- TR-26-0290 · Jun 2, 2026(Linux Kernel Güvenlik Bildirimi)
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
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/2698731d25823267c29190cb578da9296a0c0d7b
- git.kernel.org/stable/c/2920ec61c98b9476781359f05b94da84e80f54d4
- git.kernel.org/stable/c/37555690f39f78ef69af347d9aff897e07445949
- git.kernel.org/stable/c/67cdb7bd7442bd3cdc6d6088bbb2df9be2fe936c
- git.kernel.org/stable/c/716e7439a5a9b18c3ff882c2f8c834b9ced1aaec
- git.kernel.org/stable/c/77e407967cd872cd75d7e4a691908e49c8e6b4d4
- git.kernel.org/stable/c/feaf2a80e78f89ee8a3464126077ba8683b62791
Vendor advisories and official records. Exploit/PoC links are deliberately left out.