CVE-2025-40200
- Published: 2025-11-12T22:15:47.160
In the Linux kernel, the following vulnerability has been resolved:
Squashfs: reject negative file sizes in squashfs_read_inode()
Syskaller reports a “WARNING in ovl_copy_up_file” in overlayfs.
This warning is ultimately caused because the underlying Squashfs file
system returns a file with a negative file size.
This commit checks for a negative file size and returns EINVAL.
[phillip@squashfs.org.uk: only need to check 64 bit quantity]
Related CVE by CWE
No related CWE found.
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Recently Exploited Similar Vulnerabilities
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How to fix CVE-2025-40200
CVE-2025-40200 is a unknown severity vulnerability affecting the affected product.
Description: In the Linux kernel, the following vulnerability has been resolved: Squashfs: reject negative file sizes in squashfs_read_inode() Syskaller reports a “WARNING in ovl_copy_up_file” in overlayfs. This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size. This commit checks for a negative file size and returns EINVAL. […]
Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public
How to Fix:
- Check if you're running the affected product
- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access
- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)
- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations
Description: In the Linux kernel, the following vulnerability has been resolved: Squashfs: reject negative file sizes in squashfs_read_inode() Syskaller reports a “WARNING in ovl_copy_up_file” in overlayfs. This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size. This commit checks for a negative file size and returns EINVAL. […]
Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public
How to Fix:
1 Identify affected systems
- Check if you're running the affected product
2 Immediate actions
- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access
3 Verification
- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)
4 Long-term prevention
- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations
Exploit Difficulty Assessment
HARD
Time to Exploit: > 4 hours
Skills Required: Advanced security expertise
Public Exploits: Rare or not public
Vulnerability Timeline
Nov 12, 2025
Vulnerability Published
CVE details first published to NVD database
Nov 12, 2025
Imported to Database
Added to this CVE tracking system
Detection Rules & IOCs
No specific detection rules generated for this vulnerability type.
No vendor/product data available.