In the Linux kernel, the following vulnerability has been resolved:
fs/jfs: Prevent integer overflow in AG size calculation
The JFS filesystem calculates allocation group (AG) size using 1 <<
l2agsize in dbExtendFS(). When l2agsize exceeds 31 (possible with >2TB
aggregates on 32-bit systems), this 32-bit shift operation causes undefined
behavior and improper AG sizing.
On 32-bit architectures:
- Left-shifting 1 by 32+ bits results in 0 due to integer overflow
- This creates invalid AG sizes (0 or garbage values) in
sbi->bmap->db_agsize
- Subsequent block allocations would reference invalid AG structures
- Could lead to:
- Filesystem corruption during extend operations
- Kernel crashes due to invalid memory accesses
- Security vulnerabilities via malformed on-disk structures
Fix by casting to s64 before shifting:
bmp->db_agsize = (s64)1 << l2agsize;
This ensures 64-bit arithmetic even on 32-bit architectures. The cast
matches the data type of db_agsize (s64) and follows similar patterns in
JFS block calculation code.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVSS
No CVSS.
References
Configurations
No configuration.
History
03 Nov 2025, 20:18
| Type | Values Removed | Values Added |
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| References |
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12 May 2025, 17:32
| Type | Values Removed | Values Added |
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| New CVE |
Information
Published : 2025-05-09 07:16
Updated : 2025-11-03 20:18
NVD link : CVE-2025-37858
Mitre link : CVE-2025-37858
CVE.ORG link : CVE-2025-37858
JSON object : View
Products Affected
No product.
CWE
No CWE.