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Linux KernelOperating system · Linux

CVE-2026-53046

CRITICAL · 9.8 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 5.15.209 / 6.1.175 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 8 weeks old

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: ksmbd: fix use-after-free from async crypto on Qualcomm crypto engine ksmbd_crypt_message() sets a NULL completion callback on AEAD requests and does not handle the -EINPROGRESS return code from async hardware crypto engines like the Qualcomm Crypto Engine (QCE). When QCE returns -EINPROGRESS, ksmbd treats it as an error and immediately frees the request while the hardware DMA operation is still in flight. The DMA completion callback then dereferences freed memory, causing a NULL pointer crash: pc : qce_skcipher_done+0x24/0x174 lr : vchan_complete+0x230/0x27c ... el1h_64_irq+0x68/0x6c ksmbd_free_work_struct+0x20/0x118 [ksmbd] ksmbd_exit_file_cache+0x694/0xa4c [ksmbd] Use the standard crypto_wait_req() pattern with crypto_req_done() as the completion callback, matching the approach used by the SMB client in fs/smb/client/smb2ops.c. This properly handles both synchronous engines (immediate return) and async engines (-EINPROGRESS followed by callback notification).

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

A use-after-free vulnerability in ksmbd_crypt_message() occurs when async hardware crypto engines like Qualcomm Crypto Engine (QCE) return -EINPROGRESS. The code incorrectly treats this as an error and frees the request while DMA is still in flight, causing the completion callback to dereference freed memory.

MitigationApply the fix to use crypto_wait_req() with crypto_req_done() completion callback, which properly handles both synchronous and asynchronous crypto engines by waiting for -EINPROGRESS to complete before freeing resources.

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:>= 5.15, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

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. Verify ksmbd is active
    Run 'ps aux | grep ksmbd' or check if /proc/fs/ksmbd/ directory exists and contains active shares
    Affected if ksmbd daemon or kernel module is running and serving SMB connections
  2. Check kernel version
    Run 'uname -r' to obtain the running kernel version
    Affected if The kernel version predates the fix for this vulnerability (kernel mainline after the patch date)
  3. Identify hardware crypto engine in use
    Check /proc/crypto or run 'lsmod' for crypto engine modules (e.g., qce, qcrypto for Qualcomm) and examine /sys/class/crypto/ for active hardware crypto drivers
    Affected if A hardware crypto engine module like Qualcomm Crypto Engine is loaded and bound to a crypto algorithm that ksmbd uses for SMB encryption
  4. Confirm SMB encryption is enabled
    Run 'cat /proc/fs/ksmbd/shares' or use 'smbstatus' to list active shares and check if encryption is negotiated (look for 'encryption' flag in share or connection details)
    Affected if SMB encryption or message signing is enabled on at least one share, as ksmbd_crypt_message() is only invoked for encrypted SMB traffic
  5. Check for the vulnerable code pattern
    If kernel source is available, grep 'ksmbd_crypt_message' in fs/smb/ksmbd/*.c and verify whether crypto_wait_req() with crypto_req_done() callback is used; alternatively, check /proc/kallsyms for the function symbol
    Affected if The function does not implement the crypto_wait_req pattern and relies on NULL completion callbacks for AEAD requests

A system is affected if it runs ksmbd with an unpatched kernel, has hardware crypto acceleration enabled, and has SMB encryption active - the crash occurs when the async hardware crypto engine returns -EINPROGRESS and the NULL callback is dereferenced after premature request freeing.

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 5.15.209 / 6.1.175 / 6.6.141 or later
Fixed in 5.15.2096.1.1756.6.141
Interim mitigation

Apply the fix to use crypto_wait_req() with crypto_req_done() completion callback, which properly handles both synchronous and asynchronous crypto engines by waiting for -EINPROGRESS to complete before freeing resources.

Recommended fix Moderate confidence
  1. Obtain the upstream kernel patch from git.kernel.org for the ksmbd use-after-free fix in ksmbd_crypt_message()
  2. Locate the ksmbd_crypt_message() function in the kernel source (typically in fs/ksmbd/ or similar ksmbd-related path)
  3. Modify ksmbd_crypt_message() to use crypto_wait_req() with crypto_req_done() as the completion callback instead of setting NULL callback
  4. Ensure proper handling of -EINPROGRESS return code from async crypto engines like Qualcomm Crypto Engine (QCE)
  5. Apply the patch to the kernel source
  6. Rebuild the ksmbd module or kernel as appropriate
  7. Test the fix in a development environment before production deployment

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
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,860
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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-2026-53046 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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