CVE-2025-37858
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().
Does this matter?
Lower severity and a low EPSS score (0.30%). Track it; it rarely justifies an emergency change on its own.
Description
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 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.30% probability · 23th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-190
- Affected
- linux/linux kernel · debian/debian linux
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/211ed8f5e39e61f9e4d18edd64ce8005a67a1b2aPatch
- https://git.kernel.org/stable/c/3d8a45f87010a802aa214bf39702ca9d99cbf3baPatch
- https://git.kernel.org/stable/c/55edbf5dbf60a8195c21e92124c4028939ae16b2Patch
- https://git.kernel.org/stable/c/7ccf3b35274512b60ecb614e0637e76bd6f2d829Patch
- https://git.kernel.org/stable/c/7fcbf789629cdb9fbf4e2172ce31136cfed11e5ePatch
- https://git.kernel.org/stable/c/8bb29629a5e4090e1ef7199cb42db04a52802239Patch
- https://git.kernel.org/stable/c/c802a6a4009f585111f903e810b3be9c6d0da329Patch
- https://git.kernel.org/stable/c/dd07a985e2ded47b6c7d69fc93c1fe02977c8454Patch
- https://git.kernel.org/stable/c/ec34cdf4f917cc6abd306cf091f8b8361fedac88Patch
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.htmlMailing List, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.