# CVE-2025-39731: f2fs: vm_unmap_ram() may be called from an invalid context > A bug in the Linux kernel's F2FS filesystem causes a kernel panic when releasing decompression memory in an interrupt context, leading to system crashes. - **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:** 7 Sep 2025 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2025-39731, DEBIAN-CVE-2025-39731, GHSA-5c3p-rf64-5rph, ROOT-OS-UBUNTU-2404-CVE-2025-39731, UBUNTU-CVE-2025-39731 ## What is CVE-2025-39731? CVE-2025-39731 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 7 Sep 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: f2fs: vm_unmap_ram() may be called from an invalid context When testing F2FS with xfstests using UFS backed virtual disks the kernel complains sometimes that f2fs_release_decomp_mem() calls vm_unmap_ram() from an invalid context. Example trace from f2fs/007 test: f2fs/007 5s ... [12:59:38][ 8.902525] run fstests f2fs/007 [ 11.468026] BUG: sleeping function called from invalid context at mm/vmalloc.c:2978 [ 11.471849] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 68, name: irq/22-ufshcd [ 11.475357] preempt_count: 1, expected: 0 [ 11.476970] RCU nest depth: 0, expected: 0 [ 11.478531] CPU: 0 UID: 0 PID: 68 Comm: irq/22-ufshcd Tainted: G W 6.16.0-rc5-xfstests-ufs-g40f92e79b0aa #9 PREEMPT(none) [ 11.478535] Tainted: [W]=WARN [ 11.478536] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 11.478537] Call Trace: [ 11.478543] [ 11.478545] dump_stack_lvl+0x4e/0x70 [ 11.478554] __might_resched.cold+0xaf/0xbe [ 11.478557] vm_unmap_ram+0x21/0xb0 [ 11.478560] f2fs_release_decomp_mem+0x59/0x80 [ 11.478563] f2fs_free_dic+0x18/0x1a0 [ 11.478565] f2fs_finish_read_bio+0xd7/0x290 [ 11.478570] blk_update_request+0xec/0x3b0 [ 11.478574] ? sbitmap_queue_clear+0x3b/0x60 [ 11.478576] scsi_end_request+0x27/0x1a0 [ 11.478582] scsi_io_completion+0x40/0x300 [ 11.478583] ufshcd_mcq_poll_cqe_lock+0xa3/0xe0 [ 11.478588] ufshcd_sl_intr+0x194/0x1f0 [ 11.478592] ufshcd_threaded_intr+0x68/0xb0 [ 11.478594] ? __pfx_irq_thread_fn+0x10/0x10 [ 11.478599] irq_thread_fn+0x20/0x60 [ 11.478602] ? __pfx_irq_thread_fn+0x10/0x10 [ 11.478603] irq_thread+0xb9/0x180 [ 11.478605] ? __pfx_irq_thread_dtor+0x10/0x10 [ 11.478607] ? __pfx_irq_thread+0x10/0x10 [ 11.478609] kthread+0x10a/0x230 [ 11.478614] ? __pfx_kthread+0x10/0x10 [ 11.478615] ret_from_fork+0x7e/0xd0 [ 11.478619] ? __pfx_kthread+0x10/0x10 [ 11.478621] ret_from_fork_asm+0x1a/0x30 [ 11.478623] This patch modifies in_task() check inside f2fs_read_end_io() to also check if interrupts are disabled. This ensures that pages are unmapped asynchronously in an interrupt handler. ## Which versions are affected by CVE-2025-39731? It affects 2 products. Products: Debian Debian Linux, Linux kernel. ## How do I fix CVE-2025-39731? Apply the vendor's patch. ## Is CVE-2025-39731 being exploited? There is no known exploitation of CVE-2025-39731 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-2025-39731 and fix it if it is affected. What it is: CVE-2025-39731 is a medium-severity denial of service vulnerability in Debian Debian Linux, published on 7 Sep 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-2025-39731 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-2025-39731/ (Markdown: https://insights.sbomify.com/CVE-2025-39731/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39731 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39731 - OSV: https://osv.dev/vulnerability/CVE-2025-39731 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-39731/ Summaries are generated and may contain mistakes; the official description above is the record.