{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2023-54121 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2023-54121 is a high-severity memory corruption vulnerability in Linux, published on 24 Dec 2025. 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-2023-54121 and fix it if it is affected.\n\nWhat it is: CVE-2023-54121 is a high-severity memory corruption vulnerability in Linux, published on 24 Dec 2025. 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-2023-54121 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2023-54121/ (Markdown: https://insights.sbomify.com/CVE-2023-54121/index.md)","id":"CVE-2023-54121","markdown":"https://insights.sbomify.com/CVE-2023-54121/index.md","name":"CVE-2023-54121","record":{"aliases":["BELL-CVE-2023-54121","DEBIAN-CVE-2023-54121","GHSA-8482-4rvj-5h62","ROOT-OS-DEBIAN-11-CVE-2023-54121","ROOT-OS-UBUNTU-2204-CVE-2023-54121","UBUNTU-CVE-2023-54121"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"Incorrect extent map splitting in the Linux kernel btrfs filesystem can cause invalid memory states and system crashes during relocation.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix incorrect splitting in btrfs_drop_extent_map_range\n\nIn production we were seeing a variety of WARN_ON()'s in the extent_map\ncode, specifically in btrfs_drop_extent_map_range() when we have to call\nadd_extent_mapping() for our second split.\n\nConsider the following extent map layout\n\n\tPINNED\n\t[0 16K)  [32K, 48K)\n\nand then we call btrfs_drop_extent_map_range for [0, 36K), with\nskip_pinned == true.  The initial loop will have\n\n\tstart = 0\n\tend = 36K\n\tlen = 36K\n\nwe will find the [0, 16k) extent, but since we are pinned we will skip\nit, which has this code\n\n\tstart = em_end;\n\tif (end != (u64)-1)\n\t\tlen = start + len - em_end;\n\nem_end here is 16K, so now the values are\n\n\tstart = 16K\n\tlen = 16K + 36K - 16K = 36K\n\nlen should instead be 20K.  This is a problem when we find the next\nextent at [32K, 48K), we need to split this extent to leave [36K, 48k),\nhowever the code for the split looks like this\n\n\tsplit-\u003estart = start + len;\n\tsplit-\u003elen = em_end - (start + len);\n\nIn this case we have\n\n\tem_end = 48K\n\tsplit-\u003estart = 16K + 36K       // this should be 16K + 20K\n\tsplit-\u003elen = 48K - (16K + 36K) // this overflows as 16K + 36K is 52K\n\nand now we have an invalid extent_map in the tree that potentially\noverlaps other entries in the extent map.  Even in the non-overlapping\ncase we will have split-\u003estart set improperly, which will cause problems\nwith any block related calculations.\n\nWe don't actually need len in this loop, we can simply use end as our\nend point, and only adjust start up when we find a pinned extent we need\nto skip.\n\nAdjust the logic to do this, which keeps us from inserting an invalid\nextent map.\n\nWe only skip_pinned in the relocation case, so this is relatively rare,\nexcept in the case where you are running relocation a lot, which can\nhappen with auto relocation on.","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":"btrfs: fix incorrect splitting in btrfs_drop_extent_map_range","id":"CVE-2023-54121","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"memory_corruption","year":"2023"},"n_packages":0,"n_references":3,"next":{"headline":"drm/msm/dpu: Add check for cstate","id":"CVE-2023-54122"},"packages":[],"prev":{"headline":"Bluetooth: Fix race condition in hidp_session_thread","id":"CVE-2023-54120"},"products":["Linux"],"published":"2025-12-24","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"Incorrect extent map splitting in the Linux kernel btrfs filesystem can cause invalid memory states and system crashes during relocation.","url":"https://insights.sbomify.com/CVE-2023-54121/"}