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Linux KernelOperating system · Linux

CVE-2026-31463

CRITICAL · 9.8 CVSS v3.1 Published 2026-04-22
Fix available
A fix is available. Upgrade to 6.19.11 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: iomap: fix invalid folio access when i_blkbits differs from I/O granularity Commit aa35dd5cbc06 ("iomap: fix invalid folio access after folio_end_read()") partially addressed invalid folio access for folios without an ifs attached, but it did not handle the case where 1 << inode->i_blkbits matches the folio size but is different from the granularity used for the IO, which means IO can be submitted for less than the full folio for the !ifs case. In this case, the condition: if (*bytes_submitted == folio_len) ctx->cur_folio = NULL; in iomap_read_folio_iter() will not invalidate ctx->cur_folio, and iomap_read_end() will still be called on the folio even though the IO helper owns it and will finish the read on it. Fix this by unconditionally invalidating ctx->cur_folio for the !ifs case.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Linux kernel's iomap subsystem has a race condition where ctx->cur_folio is not properly invalidated when block size (i_blkbits) differs from I/O granularity. When partial I/O completes on a folio without an ifs attached, the condition checking bytes_submitted == folio_len fails to clear cur_folio, causing iomap_read_end() to be called on a folio still owned by the I/O helper, leading to potential use-after-free or invalid memory access.

MitigationApply the upstream kernel patch that unconditionally invalidates ctx->cur_folio for the !ifs case in iomap_read_folio_iter(). This is a kernel-level fix requiring recompilation and deployment of the patched kernel.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.19, < 6.19.11= 7.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version
    Run 'uname -r' or 'cat /proc/version' to obtain the running kernel version
    Affected if The kernel version is 6.19.0 through 6.19.10 (inclusive), or exactly 7.0.0 (i.e., matches >= 6.19, < 6.19.11 or = 7.0)
  2. Verify iomap subsystem is present
    Check that the kernel has iomap support by looking for CONFIG_FS_IOMAP in /boot/config-$(uname -r) or /proc/config.gz (if available), or verify /sys/kernel/debug/iomap exists
    Affected if The iomap subsystem is compiled into the kernel (this is the default for most distributions)
  3. Identify iomap source code version
    If the kernel source is available, locate fs/iomap/iterator.c and check the iomap_read_folio_iter() function for the vulnerable code pattern where cur_folio is not cleared in the !ifs (inline fs) case when bytes_submitted == folio_len
    Affected if The source code contains the vulnerable pattern where cur_folio invalidation is missing for the !ifs branch after partial I/O completes
  4. Check for folio-related I/O errors
    Monitor dmesg for kernel warnings or errors related tofolio, iomap, or memory access faults: 'dmesg | grep -i -E "(folio|iomap|use-after-free|invalid memory)"'
    Affected if The system exhibits symptoms of the race condition such as folio-related panics or memory access violations during file reads

The environment is affected if the running kernel version is 6.19.x where x < 11, or exactly 7.0, and the iomap subsystem is in use performing buffered I/O operations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.19.11 or later
Fixed in 6.19.11
Vendor patch git.kernel.org →
Interim mitigation

Apply the upstream kernel patch that unconditionally invalidates ctx->cur_folio for the !ifs case in iomap_read_folio_iter(). This is a kernel-level fix requiring recompilation and deployment of the patched kernel.

Recommended fix High confidence

Linux Kernel 6.19.11 or later (for 6.19.x branch); Linux Kernel 7.1 or later (for 7.x branch)

  1. 1. Identify the current running kernel version using `uname -r`
  2. 2. For systems running 6.19.x (>= 6.19, < 6.19.11): Upgrade to kernel version 6.19.11 or later using your distribution's package manager (e.g., `apt-get install linux-image-6.19.11`, `yum update kernel-6.19.11`, or equivalent)
  3. 3. For systems running 7.0: Upgrade to kernel version 7.1 or later
  4. 4. Reboot the system to load the new kernel
  5. 5. Verify the fix is applied by checking the kernel version (`uname -r`) and confirming it shows 6.19.11+ or 7.1+
Caveat Standard kernel upgrade risks apply - ensure compatibility with custom modules and drivers before rebooting

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,540
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-31463 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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