io_uring/rsrc: reject zero-length fixed buffer import
In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: reject zero-length fixed buffer import validate_fixed_range() admits buf_addr at the exact end of the registered region when len is zero, because the check uses strict greater-than (buf_end > imu->ubuf + imu->len). io_import_fixed() then computes offset == imu->len, which causes the bvec skip logic to advance past the last bio_vec entry and read bv_offset from out-of-bounds slab memory. Return early from io_import_fixed() when len is zero. A zero-length import has no data to transfer and should not walk the bvec array at all. BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0 Read of size 4 at addr ffff888002bcc254 by task poc/103 Call Trace: io_import_reg_buf+0x697/0x7f0 io_write_fixed+0xd9/0x250 __io_issue_sqe+0xad/0x710 io_issue_sqe+0x7d/0x1100 io_submit_sqes+0x86a/0x23c0 __do_sys_io_uring_enter+0xa98/0x1590 Allocated by task 103: The buggy address is located 12 bytes to the right of allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)
- Published
- May 1, 2026
- Updated
- Aug 5, 2026
- EPSS
- 0.2% · 5th percentile
- CWE
- CWE-125
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Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 7.1
- 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.
Affected 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 kernel6.15 and later · before 6.18.22
- linux linux kernel6.19 and later · before 6.19.12
- 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
- 6.15affected
- 8622b20f23ed165f48b8ca61503a107d17f8d585 and later · before 040a1e7e0e2f01851fec1dd2d96906f8636a9f75affected · git
- 8622b20f23ed165f48b8ca61503a107d17f8d585 and later · before 40170fc1a79c1b2e68f09ae6aac687b7305ae6f4affected · git
- 8622b20f23ed165f48b8ca61503a107d17f8d585 and later · before 111a12b422a8cfa93deabaef26fec48237163214affected · git
- before 6.15not affected · semver
- 6.18.22 and later · up to and including 6.18.*not affected · semver
- 6.19.12 and later · up to and including 6.19.*not affected · semver
- 7.0 and laternot affected · original_commit_for_fix
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | kernel | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-devel | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-devel-matched | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-modules | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-modules-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-debug-modules-extra | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-devel | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-devel-matched | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-modules | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-modules-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-64k-modules-extra | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-abi-stablelists | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-cross-headers | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug-devel | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug-devel-matched | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug-modules | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
| AlmaLinux:10 | kernel-debug-modules-core | before 6.12.0-211.18.1.el10_2 | 6.12.0-211.18.1.el10_2 |
+96
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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 | 040a1e7e0e2f01851fec1dd2d96906f8636a9f75 | Vendor (CNA) |
| Linux Linux | 111a12b422a8cfa93deabaef26fec48237163214 | Vendor (CNA) |
| Linux Linux | 40170fc1a79c1b2e68f09ae6aac687b7305ae6f4 | Vendor (CNA) |
| almalinux:kernel | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-core | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-core | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-devel-matched | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-core | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-debug-modules-extra | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-devel | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:kernel-64k-devel-matched | 6.12.0-211.18.1.el10_2 · AlmaLinux:10 | Package registry (OSV) |
| debian:linux | 6.19.12-1 · Debian:14 | Package registry (OSV) |
| red hat:kernel-64k-debug-debuginfo | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-64k-debug-devel | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-64k-debug-devel-matched | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-64k-debuginfo | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-64k-devel | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-64k-devel-matched | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debug-debuginfo | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debug-devel | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debug-devel-matched | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debuginfo | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debuginfo-common-aarch64 | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| red hat:kernel-debuginfo-common-ppc64le | 0:6.12.0-211.18.1.el10_2 · Red Hat:enterprise_linux:10.2 | Package registry (OSV) |
| rocky linux:kernel | 0:6.12.0-211.18.1.el10_2 · Rocky Linux:10 | 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).
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
- high · data can be read
- 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
- High
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-125 · Out-of-bounds ReadCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75
- git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214
- git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4
Vendor advisories and official records. Exploit/PoC links are deliberately left out.