CVE-2025-37858

Source
https://nvd.nist.gov/vuln/detail/CVE-2025-37858
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-37858.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-37858
Downstream
Related
Published
2025-05-09T07:16:06Z
Modified
2025-08-09T20:01:26Z
Summary
[none]
Details

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.

References

Affected packages