{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23249 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23249 is a medium-severity vulnerability in Linux kernel, published on 18 Mar 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-2026-23249 and fix it if it is affected.\n\nWhat it is: CVE-2026-23249 is a medium-severity vulnerability in Linux kernel, published on 18 Mar 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-2026-23249 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-2026-23249/ (Markdown: https://insights.sbomify.com/CVE-2026-23249/index.md)","id":"CVE-2026-23249","markdown":"https://insights.sbomify.com/CVE-2026-23249/index.md","name":"CVE-2026-23249","record":{"aliases":["BELL-CVE-2026-23249","DEBIAN-CVE-2026-23249","GHSA-w9wm-69p8-g28q","ROOT-OS-DEBIAN-13-CVE-2026-23249","ROOT-OS-UBUNTU-2404-CVE-2026-23249","UBUNTU-CVE-2026-23249"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel XFS","requires_auth":"low_privilege","summary":"A null pointer dereference in the Linux kernel XFS filesystem can cause a system crash during btree revalidation.","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":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: check for deleted cursors when revalidating two btrees\n\nThe free space and inode btree repair functions will rebuild both btrees\nat the same time, after which it needs to evaluate both btrees to\nconfirm that the corruptions are gone.\n\nHowever, Jiaming Zhang ran syzbot and produced a crash in the second\nxchk_allocbt call.  His root-cause analysis is as follows (with minor\ncorrections):\n\n In xrep_revalidate_allocbt(), xchk_allocbt() is called twice (first\n for BNOBT, second for CNTBT). The cause of this issue is that the\n first call nullified the cursor required by the second call.\n\n Let's first enter xrep_revalidate_allocbt() via following call chain:\n\n xfs_file_ioctl() -\u003e\n xfs_ioc_scrubv_metadata() -\u003e\n xfs_scrub_metadata() -\u003e\n `sc-\u003eops-\u003erepair_eval(sc)` -\u003e\n xrep_revalidate_allocbt()\n\n xchk_allocbt() is called twice in this function. In the first call:\n\n /* Note that sc-\u003esm-\u003esm_type is XFS_SCRUB_TYPE_BNOPT now */\n xchk_allocbt() -\u003e\n xchk_btree() -\u003e\n `bs-\u003escrub_rec(bs, recp)` -\u003e\n xchk_allocbt_rec() -\u003e\n xchk_allocbt_xref() -\u003e\n xchk_allocbt_xref_other()\n\n since sm_type is XFS_SCRUB_TYPE_BNOBT, pur is set to \u0026sc-\u003esa.cnt_cur.\n Kernel called xfs_alloc_get_rec() and returned -EFSCORRUPTED. Call\n chain:\n\n xfs_alloc_get_rec() -\u003e\n xfs_btree_get_rec() -\u003e\n xfs_btree_check_block() -\u003e\n (XFS_IS_CORRUPT || XFS_TEST_ERROR), the former is false and the latter\n is true, return -EFSCORRUPTED. This should be caused by\n ioctl$XFS_IOC_ERROR_INJECTION I guess.\n\n Back to xchk_allocbt_xref_other(), after receiving -EFSCORRUPTED from\n xfs_alloc_get_rec(), kernel called xchk_should_check_xref(). In this\n function, *curpp (points to sc-\u003esa.cnt_cur) is nullified.\n\n Back to xrep_revalidate_allocbt(), since sc-\u003esa.cnt_cur has been\n nullified, it then triggered null-ptr-deref via xchk_allocbt() (second\n call) -\u003e xchk_btree().\n\nSo.  The bnobt revalidation failed on a cross-reference attempt, so we\ndeleted the cntbt cursor, and then crashed when we tried to revalidate\nthe cntbt.  Therefore, check for a null cntbt cursor before that\nrevalidation, and mark the repair incomplete.  Also we can ignore the\nsecond tree entirely if the first tree was rebuilt but is already\ncorrupt.\n\nApply the same fix to xrep_revalidate_iallocbt because it has the same\nproblem.","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":"xfs: check for deleted cursors when revalidating two btrees","id":"CVE-2026-23249","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"xfs: check return value of xchk_scrub_create_subord","id":"CVE-2026-23250"},"packages":[],"prev":{"headline":"perf/core: Fix refcount bug and potential UAF in perf_mmap","id":"CVE-2026-23248"},"products":["Linux"],"published":"2026-03-18","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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A null pointer dereference in the Linux kernel XFS filesystem can cause a system crash during btree revalidation.","url":"https://insights.sbomify.com/CVE-2026-23249/"}