# CVE-2025-37742: jfs: Fix uninit-value access of imap allocated in the diMount() function > An uninitialized memory access in the Linux kernel JFS filesystem allows attackers to potentially disclose sensitive kernel memory contents. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 1 May 2025 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2025-37742, DEBIAN-CVE-2025-37742, GHSA-69cq-v3pw-hrr3, ROOT-OS-DEBIAN-11-CVE-2025-37742, ROOT-OS-DEBIAN-12-CVE-2025-37742, ROOT-OS-UBUNTU-2204-CVE-2025-37742, ROOT-OS-UBUNTU-2404-CVE-2025-37742, UBUNTU-CVE-2025-37742 ## What is CVE-2025-37742? CVE-2025-37742 is a medium-severity vulnerability in Debian Debian Linux, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: jfs: Fix uninit-value access of imap allocated in the diMount() function syzbot reports that hex_dump_to_buffer is using uninit-value: ===================================================== BUG: KMSAN: uninit-value in hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 hex_dump_to_buffer+0x888/0x1100 lib/hexdump.c:171 print_hex_dump+0x13d/0x3e0 lib/hexdump.c:276 diFree+0x5ba/0x4350 fs/jfs/jfs_imap.c:876 jfs_evict_inode+0x510/0x550 fs/jfs/inode.c:156 evict+0x723/0xd10 fs/inode.c:796 iput_final fs/inode.c:1946 [inline] iput+0x97b/0xdb0 fs/inode.c:1972 txUpdateMap+0xf3e/0x1150 fs/jfs/jfs_txnmgr.c:2367 txLazyCommit fs/jfs/jfs_txnmgr.c:2664 [inline] jfs_lazycommit+0x627/0x11d0 fs/jfs/jfs_txnmgr.c:2733 kthread+0x6b9/0xef0 kernel/kthread.c:464 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Uninit was created at: slab_post_alloc_hook mm/slub.c:4121 [inline] slab_alloc_node mm/slub.c:4164 [inline] __kmalloc_cache_noprof+0x8e3/0xdf0 mm/slub.c:4320 kmalloc_noprof include/linux/slab.h:901 [inline] diMount+0x61/0x7f0 fs/jfs/jfs_imap.c:105 jfs_mount+0xa8e/0x11d0 fs/jfs/jfs_mount.c:176 jfs_fill_super+0xa47/0x17c0 fs/jfs/super.c:523 get_tree_bdev_flags+0x6ec/0x910 fs/super.c:1636 get_tree_bdev+0x37/0x50 fs/super.c:1659 jfs_get_tree+0x34/0x40 fs/jfs/super.c:635 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814 do_new_mount+0x71f/0x15e0 fs/namespace.c:3560 path_mount+0x742/0x1f10 fs/namespace.c:3887 do_mount fs/namespace.c:3900 [inline] __do_sys_mount fs/namespace.c:4111 [inline] __se_sys_mount+0x71f/0x800 fs/namespace.c:4088 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4088 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f ===================================================== The reason is that imap is not properly initialized after memory allocation. It will cause the snprintf() function to write uninitialized data into linebuf within hex_dump_to_buffer(). Fix this by using kzalloc instead of kmalloc to clear its content at the beginning in diMount(). Weakness: CWE-908 (Use of Uninitialized Resource) ## Which versions are affected by CVE-2025-37742? It affects 2 products. Products: Debian Debian Linux, Linux kernel. ## How do I fix CVE-2025-37742? Apply the vendor's patch. ## Is CVE-2025-37742 being exploited? There is no known exploitation of CVE-2025-37742 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-37742 and fix it if it is affected. What it is: CVE-2025-37742 is a medium-severity vulnerability in Debian Debian Linux, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2025-37742 in the wild and no public exploit code. Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2025-37742/ (Markdown: https://insights.sbomify.com/CVE-2025-37742/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37742 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37742 - OSV: https://osv.dev/vulnerability/CVE-2025-37742 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-37742/ Summaries are generated and may contain mistakes; the official description above is the record.