# CVE-2024-46733: btrfs: fix qgroup reserve leaks in cow_file_range > A resource leak in the Linux kernel's Btrfs filesystem can cause unmount failures and system instability, requiring a kernel patch. - **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:** 18 Sep 2024 - **Updated:** 11 May 2026 - **Also known as:** AZL-67833, BELL-CVE-2024-46733, DEBIAN-CVE-2024-46733, GHSA-p357-q4ph-xr92, ROOT-OS-DEBIAN-11-CVE-2024-46733, ROOT-OS-UBUNTU-2204-CVE-2024-46733, UBUNTU-CVE-2024-46733 ## What is CVE-2024-46733? CVE-2024-46733 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Sep 2024. 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: btrfs: fix qgroup reserve leaks in cow_file_range In the buffered write path, the dirty page owns the qgroup reserve until it creates an ordered_extent. Therefore, any errors that occur before the ordered_extent is created must free that reservation, or else the space is leaked. The fstest generic/475 exercises various IO error paths, and is able to trigger errors in cow_file_range where we fail to get to allocating the ordered extent. Note that because we *do* clear delalloc, we are likely to remove the inode from the delalloc list, so the inodes/pages to not have invalidate/launder called on them in the commit abort path. This results in failures at the unmount stage of the test that look like: BTRFS: error (device dm-8 state EA) in cleanup_transaction:2018: errno=-5 IO failure BTRFS: error (device dm-8 state EA) in btrfs_replace_file_extents:2416: errno=-5 IO failure BTRFS warning (device dm-8 state EA): qgroup 0/5 has unreleased space, type 0 rsv 28672 ------------[ cut here ]------------ WARNING: CPU: 3 PID: 22588 at fs/btrfs/disk-io.c:4333 close_ctree+0x222/0x4d0 [btrfs] Modules linked in: btrfs blake2b_generic libcrc32c xor zstd_compress raid6_pq CPU: 3 PID: 22588 Comm: umount Kdump: loaded Tainted: G W 6.10.0-rc7-gab56fde445b8 #21 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 RIP: 0010:close_ctree+0x222/0x4d0 [btrfs] RSP: 0018:ffffb4465283be00 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffffa1a1818e1000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffb4465283bbe0 RDI: ffffa1a19374fcb8 RBP: ffffa1a1818e13c0 R08: 0000000100028b16 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000003 R12: ffffa1a18ad7972c R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f9168312b80(0000) GS:ffffa1a4afcc0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f91683c9140 CR3: 000000010acaa000 CR4: 00000000000006f0 Call Trace: ? close_ctree+0x222/0x4d0 [btrfs] ? __warn.cold+0x8e/0xea ? close_ctree+0x222/0x4d0 [btrfs] ? report_bug+0xff/0x140 ? handle_bug+0x3b/0x70 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? close_ctree+0x222/0x4d0 [btrfs] generic_shutdown_super+0x70/0x160 kill_anon_super+0x11/0x40 btrfs_kill_super+0x11/0x20 [btrfs] deactivate_locked_super+0x2e/0xa0 cleanup_mnt+0xb5/0x150 task_work_run+0x57/0x80 syscall_exit_to_user_mode+0x121/0x130 do_syscall_64+0xab/0x1a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f916847a887 ---[ end trace 0000000000000000 ]--- BTRFS error (device dm-8 state EA): qgroup reserved space leaked Cases 2 and 3 in the out_reserve path both pertain to this type of leak and must free the reserved qgroup data. Because it is already an error path, I opted not to handle the possible errors in btrfs_free_qgroup_data. Weakness: CWE-667 (Improper Locking) ## Which versions are affected by CVE-2024-46733? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2024-46733? Apply the vendor's patch. ## Is CVE-2024-46733 being exploited? There is no known exploitation of CVE-2024-46733 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-46733 and fix it if it is affected. What it is: CVE-2024-46733 is a medium-severity denial of service vulnerability in Linux kernel, published on 18 Sep 2024. 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-2024-46733 in the wild and no public exploit code. Affected product: Linux kernel. 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-2024-46733/ (Markdown: https://insights.sbomify.com/CVE-2024-46733/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-46733 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-46733 - OSV: https://osv.dev/vulnerability/CVE-2024-46733 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-46733/ Summaries are generated and may contain mistakes; the official description above is the record.