{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-45942 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-45942 is a high-severity vulnerability in Linux kernel, published on 27 May 2026. 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-2026-45942 and fix it if it is affected.\n\nWhat it is: CVE-2026-45942 is a high-severity vulnerability in Linux kernel, published on 27 May 2026. 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-2026-45942 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-2026-45942/ (Markdown: https://insights.sbomify.com/CVE-2026-45942/index.md)","id":"CVE-2026-45942","markdown":"https://insights.sbomify.com/CVE-2026-45942/index.md","name":"CVE-2026-45942","record":{"aliases":["AZL-88469","BELL-CVE-2026-45942","DEBIAN-CVE-2026-45942","GHSA-w5q7-xvcj-p6c8","ROOT-OS-DEBIAN-11-CVE-2026-45942","ROOT-OS-DEBIAN-12-CVE-2026-45942","ROOT-OS-UBUNTU-2204-CVE-2026-45942","ROOT-OS-UBUNTU-2404-CVE-2026-45942","UBUNTU-CVE-2026-45942"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel ext4","requires_auth":"low_privilege","summary":"A race condition in the Linux kernel ext4 filesystem can cause bitmap inconsistencies and potential denial of service under mixed huge-page workloads.","user_interaction":"not_required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"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":[{"id":"CWE-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix e4b bitmap inconsistency reports\n\nA bitmap inconsistency issue was observed during stress tests under\nmixed huge-page workloads. Ext4 reported multiple e4b bitmap check\nfailures like:\n\next4_mb_complex_scan_group:2508: group 350, 8179 free clusters as\nper group info. But got 8192 blocks\n\nAnalysis and experimentation confirmed that the issue is caused by a\nrace condition between page migration and bitmap modification. Although\nthis timing window is extremely narrow, it is still hit in practice:\n\nfolio_lock                        ext4_mb_load_buddy\n__migrate_folio\n  check ref count\n  folio_mc_copy                     __filemap_get_folio\n                                      folio_try_get(folio)\n                                  ......\n                                  mb_mark_used\n                                  ext4_mb_unload_buddy\n  __folio_migrate_mapping\n    folio_ref_freeze\nfolio_unlock\n\nThe root cause of this issue is that the fast path of load_buddy only\nincrements the folio's reference count, which is insufficient to prevent\nconcurrent folio migration. We observed that the folio migration process\nacquires the folio lock. Therefore, we can determine whether to take the\nfast path in load_buddy by checking the lock status. If the folio is\nlocked, we opt for the slow path (which acquires the lock) to close this\nconcurrency window.\n\nAdditionally, this change addresses the following issues:\n\nWhen the DOUBLE_CHECK macro is enabled to inspect bitmap-related\nissues, the following error may be triggered:\n\ncorruption in group 324 at byte 784(6272): f in copy != ff on\ndisk/prealloc\n\nAnalysis reveals that this is a false positive. There is a specific race\nwindow where the bitmap and the group descriptor become momentarily\ninconsistent, leading to this error report:\n\next4_mb_load_buddy                   ext4_mb_load_buddy\n  __filemap_get_folio(create|lock)\n    folio_lock\n  ext4_mb_init_cache\n    folio_mark_uptodate\n                                     __filemap_get_folio(no lock)\n                                     ......\n                                     mb_mark_used\n                                       mb_mark_used_double\n  mb_cmp_bitmaps\n                                       mb_set_bits(e4b-\u003ebd_bitmap)\n  folio_unlock\n\nThe original logic assumed that since mb_cmp_bitmaps is called when the\nbitmap is newly loaded from disk, the folio lock would be sufficient to\nprevent concurrent access. However, this overlooks a specific race\ncondition: if another process attempts to load buddy and finds the folio\nis already in an uptodate state, it will immediately begin using it without\nholding folio lock.","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":"ext4: fix e4b bitmap inconsistency reports","id":"CVE-2026-45942","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"race_condition","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"erofs: fix inline data read failure for ztailpacking pclusters","id":"CVE-2026-45943"},"packages":[],"prev":{"headline":"tpm: tpm_i2c_infineon: Fix locality leak on get_burstcount() failure","id":"CVE-2026-45941"},"products":["Linux"],"published":"2026-05-27","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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A race condition in the Linux kernel ext4 filesystem can cause bitmap inconsistencies and potential denial of service under mixed huge-page workloads.","url":"https://insights.sbomify.com/CVE-2026-45942/"}