{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2024-38636 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2024-38636 is a medium-severity vulnerability in Linux kernel, published on 21 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2024-38636 and fix it if it is affected.\n\nWhat it is: CVE-2024-38636 is a medium-severity vulnerability in Linux kernel, published on 21 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2024-38636 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. 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.\n2. 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.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2024-38636/ (Markdown: https://insights.sbomify.com/CVE-2024-38636/index.md)","id":"CVE-2024-38636","markdown":"https://insights.sbomify.com/CVE-2024-38636/index.md","name":"CVE-2024-38636","record":{"aliases":["BELL-CVE-2024-38636","DEBIAN-CVE-2024-38636","GHSA-pwgj-c4vj-63r9","UBUNTU-CVE-2024-38636"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel filesystem","requires_auth":"low_privilege","summary":"A flaw in the Linux kernel's F2FS filesystem causes a kernel warning and potential crash when reading from multi-device setups with zero block addresses.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: multidev: fix to recognize valid zero block address\n\nAs reported by Yi Zhang in mailing list [1], kernel warning was catched\nduring zbd/010 test as below:\n\n./check zbd/010\nzbd/010 (test gap zone support with F2FS)                    [failed]\n    runtime    ...  3.752s\n    something found in dmesg:\n    [ 4378.146781] run blktests zbd/010 at 2024-02-18 11:31:13\n    [ 4378.192349] null_blk: module loaded\n    [ 4378.209860] null_blk: disk nullb0 created\n    [ 4378.413285] scsi_debug:sdebug_driver_probe: scsi_debug: trim\npoll_queues to 0. poll_q/nr_hw = (0/1)\n    [ 4378.422334] scsi host15: scsi_debug: version 0191 [20210520]\n                     dev_size_mb=1024, opts=0x0, submit_queues=1, statistics=0\n    [ 4378.434922] scsi 15:0:0:0: Direct-Access-ZBC Linux\nscsi_debug       0191 PQ: 0 ANSI: 7\n    [ 4378.443343] scsi 15:0:0:0: Power-on or device reset occurred\n    [ 4378.449371] sd 15:0:0:0: Attached scsi generic sg5 type 20\n    [ 4378.449418] sd 15:0:0:0: [sdf] Host-managed zoned block device\n    ...\n    (See '/mnt/tests/gitlab.com/api/v4/projects/19168116/repository/archive.zip/storage/blktests/blk/blktests/results/nodev/zbd/010.dmesg'\n\nWARNING: CPU: 22 PID: 44011 at fs/iomap/iter.c:51\nCPU: 22 PID: 44011 Comm: fio Not tainted 6.8.0-rc3+ #1\nRIP: 0010:iomap_iter+0x32b/0x350\nCall Trace:\n \u003cTASK\u003e\n __iomap_dio_rw+0x1df/0x830\n f2fs_file_read_iter+0x156/0x3d0 [f2fs]\n aio_read+0x138/0x210\n io_submit_one+0x188/0x8c0\n __x64_sys_io_submit+0x8c/0x1a0\n do_syscall_64+0x86/0x170\n entry_SYSCALL_64_after_hwframe+0x6e/0x76\n\nShinichiro Kawasaki helps to analyse this issue and proposes a potential\nfixing patch in [2].\n\nQuoted from reply of Shinichiro Kawasaki:\n\n\"I confirmed that the trigger commit is dbf8e63f48af as Yi reported. I took a\nlook in the commit, but it looks fine to me. So I thought the cause is not\nin the commit diff.\n\nI found the WARN is printed when the f2fs is set up with multiple devices,\nand read requests are mapped to the very first block of the second device in the\ndirect read path. In this case, f2fs_map_blocks() and f2fs_map_blocks_cached()\nmodify map-\u003em_pblk as the physical block address from each block device. It\nbecomes zero when it is mapped to the first block of the device. However,\nf2fs_iomap_begin() assumes that map-\u003em_pblk is the physical block address of the\nwhole f2fs, across the all block devices. It compares map-\u003em_pblk against\nNULL_ADDR == 0, then go into the unexpected branch and sets the invalid\niomap-\u003elength. The WARN catches the invalid iomap-\u003elength.\n\nThis WARN is printed even for non-zoned block devices, by following steps.\n\n - Create two (non-zoned) null_blk devices memory backed with 128MB size each:\n   nullb0 and nullb1.\n # mkfs.f2fs /dev/nullb0 -c /dev/nullb1\n # mount -t f2fs /dev/nullb0 \"${mount_dir}\"\n # dd if=/dev/zero of=\"${mount_dir}/test.dat\" bs=1M count=192\n # dd if=\"${mount_dir}/test.dat\" of=/dev/null bs=1M count=192 iflag=direct\n\n...\"\n\nSo, the root cause of this issue is: when multi-devices feature is on,\nf2fs_map_blocks() may return zero blkaddr in non-primary device, which is\na verified valid block address, however, f2fs_iomap_begin() treats it as\nan invalid block address, and then it triggers the warning in iomap\nframework code.\n\nFinally, as discussed, we decide to use a more simple and direct way that\nchecking (map.m_flags \u0026 F2FS_MAP_MAPPED) condition instead of\n(map.m_pblk != NULL_ADDR) to fix this issue.\n\nThanks a lot for the effort of Yi Zhang and Shinichiro Kawasaki on this\nissue.\n\n[1] https://lore.kernel.org/linux-f2fs-devel/CAHj4cs-kfojYC9i0G73PRkYzcxCTex=-vugRFeP40g_URGvnfQ@mail.gmail.com/\n[2] https://lore.kernel.org/linux-f2fs-devel/gngdj77k4picagsfdtiaa7gpgnup6fsgwzsltx6milmhegmjff@iax2n4wvrqye/","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"f2fs: multidev: fix to recognize valid zero block address","id":"CVE-2024-38636","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2024"},"n_packages":0,"n_references":4,"next":{"headline":"greybus: lights: check return of get_channel_from_mode","id":"CVE-2024-38637"},"packages":[],"prev":{"headline":"soundwire: cadence: fix invalid PDI offset","id":"CVE-2024-38635"},"products":["Linux"],"published":"2024-06-21","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A flaw in the Linux kernel's F2FS filesystem causes a kernel warning and potential crash when reading from multi-device setups with zero block addresses.","url":"https://insights.sbomify.com/CVE-2024-38636/"}