{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47638 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47638 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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-2021-47638 and fix it if it is affected.\n\nWhat it is: CVE-2021-47638 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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-2021-47638 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-2021-47638/ (Markdown: https://insights.sbomify.com/CVE-2021-47638/index.md)","id":"CVE-2021-47638","markdown":"https://insights.sbomify.com/CVE-2021-47638/index.md","name":"CVE-2021-47638","record":{"aliases":["DEBIAN-CVE-2021-47638","GHSA-qm9f-hj62-fcm2","UBUNTU-CVE-2021-47638"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","code_execution"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A double free vulnerability in the Linux kernel's UBIFS filesystem allows attackers to cause a denial of service or potentially execute arbitrary code.","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-415","name":"Double Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: rename_whiteout: Fix double free for whiteout_ui-\u003edata\n\n'whiteout_ui-\u003edata' will be freed twice if space budget fail for\nrename whiteout operation as following process:\n\nrename_whiteout\n  dev = kmalloc\n  whiteout_ui-\u003edata = dev\n  kfree(whiteout_ui-\u003edata)  // Free first time\n  iput(whiteout)\n    ubifs_free_inode\n      kfree(ui-\u003edata)\t    // Double free!\n\nKASAN reports:\n==================================================================\nBUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70\nCall Trace:\n  kfree+0x117/0x490\n  ubifs_free_inode+0x4f/0x70 [ubifs]\n  i_callback+0x30/0x60\n  rcu_do_batch+0x366/0xac0\n  __do_softirq+0x133/0x57f\n\nAllocated by task 1506:\n  kmem_cache_alloc_trace+0x3c2/0x7a0\n  do_rename+0x9b7/0x1150 [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nFreed by task 1506:\n  kfree+0x117/0x490\n  do_rename.cold+0x53/0x8a [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nThe buggy address belongs to the object at ffff88810238bed8 which\nbelongs to the cache kmalloc-8 of size 8\n==================================================================\n\nLet ubifs_free_inode() free 'whiteout_ui-\u003edata'. BTW, delete unused\nassignment 'whiteout_ui-\u003edata_len = 0', process 'ubifs_evict_inode()\n-\u003e ubifs_jnl_delete_inode() -\u003e ubifs_jnl_write_inode()' doesn't need it\n(because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release',\n and the nlink of whiteout inode is 0).","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":"ubifs: rename_whiteout: Fix double free for whiteout_ui-\u003edata","id":"CVE-2021-47638","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2021"},"n_packages":0,"n_references":8,"next":{"headline":"KVM: x86/mmu: Zap _all_ roots when unmapping gfn range in TDP MMU","id":"CVE-2021-47639"},"packages":[],"prev":{"headline":"ubifs: Fix deadlock in concurrent rename whiteout and inode writeback","id":"CVE-2021-47637"},"products":["Linux"],"published":"2025-02-26","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":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A double free vulnerability in the Linux kernel's UBIFS filesystem allows attackers to cause a denial of service or potentially execute arbitrary code.","url":"https://insights.sbomify.com/CVE-2021-47638/"}