{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-31703 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-31703 is a high-severity use after free vulnerability in Linux kernel, published on 1 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-2026-31703 and fix it if it is affected.\n\nWhat it is: CVE-2026-31703 is a high-severity use after free vulnerability in Linux kernel, published on 1 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-2026-31703 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-2026-31703/ (Markdown: https://insights.sbomify.com/CVE-2026-31703/index.md)","id":"CVE-2026-31703","markdown":"https://insights.sbomify.com/CVE-2026-31703/index.md","name":"CVE-2026-31703","record":{"aliases":["BELL-CVE-2026-31703","DEBIAN-CVE-2026-31703","GHSA-77jh-978m-wqhm","UBUNTU-CVE-2026-31703"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel writeback subsystem allows attackers to potentially execute arbitrary code or escalate privileges.","user_interaction":"not_required","vuln_class":"use_after_free"},"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-825","name":"Expired Pointer Dereference"},{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nwriteback: Fix use after free in inode_switch_wbs_work_fn()\n\ninode_switch_wbs_work_fn() has a loop like:\n\n  wb_get(new_wb);\n  while (1) {\n    list = llist_del_all(\u0026new_wb-\u003eswitch_wbs_ctxs);\n    /* Nothing to do? */\n    if (!list)\n      break;\n    ... process the items ...\n  }\n\nNow adding of items to the list looks like:\n\nwb_queue_isw()\n  if (llist_add(\u0026isw-\u003elist, \u0026wb-\u003eswitch_wbs_ctxs))\n    queue_work(isw_wq, \u0026wb-\u003eswitch_work);\n\nBecause inode_switch_wbs_work_fn() loops when processing isw items, it\ncan happen that wb-\u003eswitch_work is pending while wb-\u003eswitch_wbs_ctxs is\nempty. This is a problem because in that case wb can get freed (no isw\nitems -\u003e no wb reference) while the work is still pending causing\nuse-after-free issues.\n\nWe cannot just fix this by cancelling work when freeing wb because that\ncould still trigger problematic 0 -\u003e 1 transitions on wb refcount due to\nwb_get() in inode_switch_wbs_work_fn(). It could be all handled with\nmore careful code but that seems unnecessarily complex so let's avoid\nthat until it is proven that the looping actually brings practical\nbenefit. Just remove the loop from inode_switch_wbs_work_fn() instead.\nThat way when wb_queue_isw() queues work, we are guaranteed we have\nadded the first item to wb-\u003eswitch_wbs_ctxs and nobody is going to\nremove it (and drop the wb reference it holds) until the queued work\nruns.","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":"writeback: Fix use after free in inode_switch_wbs_work_fn()","id":"CVE-2026-31703","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":6,"next":{"headline":"ksmbd: use check_add_overflow() to prevent u16 DACL size overflow","id":"CVE-2026-31704"},"packages":[],"prev":{"headline":"f2fs: fix use-after-free of sbi in f2fs_compress_write_end_io()","id":"CVE-2026-31702"},"products":["Linux"],"published":"2026-05-01","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":"2026-08-20","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel writeback subsystem allows attackers to potentially execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2026-31703/"}