{"id":"CVE-2025-37858","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-37858","generatedAt":"2026-10-28T10:37:19.218Z","title":"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().","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/jfs: Prevent integer overflow in AG size calculation\n\nThe JFS filesystem calculates allocation group (AG) size using 1 <<\nl2agsize in dbExtendFS(). When l2agsize exceeds 31 (possible with >2TB\naggregates on 32-bit systems), this 32-bit shift operation causes undefined\nbehavior and improper AG sizing.\n\nOn 32-bit architectures:\n- Left-shifting 1 by 32+ bits results in 0 due to integer overflow\n- This creates invalid AG sizes (0 or garbage values) in\nsbi->bmap->db_agsize\n- Subsequent block allocations would reference invalid AG structures\n- Could lead to:\n  - Filesystem corruption during extend operations\n  - Kernel crashes due to invalid memory accesses\n  - Security vulnerabilities via malformed on-disk structures\n\nFix by casting to s64 before shifting:\nbmp->db_agsize = (s64)1 << l2agsize;\n\nThis ensures 64-bit arithmetic even on 32-bit architectures. The cast\nmatches the data type of db_agsize (s64) and follows similar patterns in\nJFS block calculation code.\n\nFound by Linux Verification Center (linuxtesting.org) with SVACE.","published":"2025-05-09T07:16:07.000Z","lastModified":"2026-06-17T09:15:35.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-190"],"affected":["linux/linux kernel","debian/debian linux"],"epss":{"score":0.00314,"percentile":0.24152,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/211ed8f5e39e61f9e4d18edd64ce8005a67a1b2a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3d8a45f87010a802aa214bf39702ca9d99cbf3ba","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/55edbf5dbf60a8195c21e92124c4028939ae16b2","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7ccf3b35274512b60ecb614e0637e76bd6f2d829","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7fcbf789629cdb9fbf4e2172ce31136cfed11e5e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8bb29629a5e4090e1ef7199cb42db04a52802239","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c802a6a4009f585111f903e810b3be9c6d0da329","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dd07a985e2ded47b6c7d69fc93c1fe02977c8454","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ec34cdf4f917cc6abd306cf091f8b8361fedac88","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-37858","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}