dbcve.org
Numeric ErrorsWeakness · CWE-189

CVE-2025-6603

MEDIUM · 5.3 CVSS v3.1 Published 2025-06-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
55/100
Remediation priority · Elevated
Zero-click

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
A vulnerability was found in coldfunction qCUDA up to db0085400c2f2011eed46fbc04fdc0873141688e. It has been rated as problematic. Affected by this issue is the function qcow_make_empty of the file qCUDA/qcu-device/block/qcow.c. The manipulation of the argument s->l1_size leads to integer overflow. The attack needs to be approached locally. This product is using a rolling release to provide continious delivery. Therefore, no version details for affected nor updated releases are available.

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 · moderate confidence

Integer overflow vulnerability in qCUDA's qcow_make_empty function in qcu-device/block/qcow.c. The s->l1_size argument is not properly validated before use, allowing an attacker to trigger overflow conditions via local access.

MitigationImplement proper bounds checking and validation on the s->l1_size value to prevent integer overflow. Use safe arithmetic operations or validate that the size falls within acceptable bounds before allocation or computation.

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

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

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

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. Identify if qCUDA is installed
    Search for qCUDA components on the system. Look for directories named 'qcu-device' or files named 'qcow.c', and check for qCUDA packages or binaries using 'ls -la /path/to/qcu*' or 'dpkg -l | grep qcuda' / 'rpm -qa | grep qcuda'
    Affected if qCUDA software is present on the system
  2. Locate the qcow.c source file
    Search for the file qcow.c in qcu-device/block/ directory. Use 'find / -path '*/qcu-device/block/qcow.c' 2>/dev/null' to locate the affected source file
    Affected if The file qcu-device/block/qcow.c exists on the system and contains the vulnerable qcow_make_empty function
  3. Verify qcow block driver or module is in use
    Check if qcow block driver or any qCUDA block device backend is active. Use 'lsmod' to list loaded modules or check for qcow-related processes with 'ps aux | grep -i qcow'
    Affected if The qcow block driver or qCUDA block backend is loaded or actively processing disk images
  4. Inspect L1 table size configuration
    Examine any qcow image files or configuration that specifies L1 table size. Use 'qemu-img info <imagefile>' on qcow2 images or inspect configuration files that may set s->l1_size parameters
    Affected if qcow images are being created or manipulated with custom or large L1 table sizes without proper bounds validation
  5. Check for qcow_make_empty function calls
    Review application logs, traces, or code that invokes the qcow_make_empty function, particularly from local users who might provide l1_size values. Search logs for 'qcow_make_empty' or 'l1_size' entries
    Affected if Local users or processes can trigger qcow_make_empty with user-controlled l1_size values

A system is affected if qCUDA is installed and the qcow block driver is in use, allowing local attackers to trigger the integer overflow via the unvalidated s->l1_size in qcow_make_empty.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper bounds checking and validation on the s->l1_size value to prevent integer overflow. Use safe arithmetic operations or validate that the size falls within acceptable bounds before allocation or computation.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2025-6603 in production — separate from our analysis above.

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