{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-46958 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-46958 is a high-severity use after free vulnerability in Linux kernel, published on 27 Feb 2024. 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-2021-46958 and fix it if it is affected.\n\nWhat it is: CVE-2021-46958 is a high-severity use after free vulnerability in Linux kernel, published on 27 Feb 2024. 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-2021-46958 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-2021-46958/ (Markdown: https://insights.sbomify.com/CVE-2021-46958/index.md)","id":"CVE-2021-46958","markdown":"https://insights.sbomify.com/CVE-2021-46958/index.md","name":"CVE-2021-46958","record":{"aliases":["DEBIAN-CVE-2021-46958","GHSA-gmfg-g4f3-5fg9","UBUNTU-CVE-2021-46958"],"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 race condition in the Linux kernel's Btrfs filesystem can lead to a use-after-free, potentially causing system crashes or arbitrary code execution.","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-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix race between transaction aborts and fsyncs leading to use-after-free\n\nThere is a race between a task aborting a transaction during a commit,\na task doing an fsync and the transaction kthread, which leads to an\nuse-after-free of the log root tree. When this happens, it results in a\nstack trace like the following:\n\n  BTRFS info (device dm-0): forced readonly\n  BTRFS warning (device dm-0): Skipping commit of aborted transaction.\n  BTRFS: error (device dm-0) in cleanup_transaction:1958: errno=-5 IO failure\n  BTRFS warning (device dm-0): lost page write due to IO error on /dev/mapper/error-test (-5)\n  BTRFS warning (device dm-0): Skipping commit of aborted transaction.\n  BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0xa4e8 len 4096 err no 10\n  BTRFS error (device dm-0): error writing primary super block to device 1\n  BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e000 len 4096 err no 10\n  BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e008 len 4096 err no 10\n  BTRFS warning (device dm-0): direct IO failed ino 261 rw 0,0 sector 0x12e010 len 4096 err no 10\n  BTRFS: error (device dm-0) in write_all_supers:4110: errno=-5 IO failure (1 errors while writing supers)\n  BTRFS: error (device dm-0) in btrfs_sync_log:3308: errno=-5 IO failure\n  general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b68: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI\n  CPU: 2 PID: 2458471 Comm: fsstress Not tainted 5.12.0-rc5-btrfs-next-84 #1\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:__mutex_lock+0x139/0xa40\n  Code: c0 74 19 (...)\n  RSP: 0018:ffff9f18830d7b00 EFLAGS: 00010202\n  RAX: 6b6b6b6b6b6b6b68 RBX: 0000000000000001 RCX: 0000000000000002\n  RDX: ffffffffb9c54d13 RSI: 0000000000000000 RDI: 0000000000000000\n  RBP: ffff9f18830d7bc0 R08: 0000000000000000 R09: 0000000000000000\n  R10: ffff9f18830d7be0 R11: 0000000000000001 R12: ffff8c6cd199c040\n  R13: ffff8c6c95821358 R14: 00000000fffffffb R15: ffff8c6cbcf01358\n  FS:  00007fa9140c2b80(0000) GS:ffff8c6fac600000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007fa913d52000 CR3: 000000013d2b4003 CR4: 0000000000370ee0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   ? __btrfs_handle_fs_error+0xde/0x146 [btrfs]\n   ? btrfs_sync_log+0x7c1/0xf20 [btrfs]\n   ? btrfs_sync_log+0x7c1/0xf20 [btrfs]\n   btrfs_sync_log+0x7c1/0xf20 [btrfs]\n   btrfs_sync_file+0x40c/0x580 [btrfs]\n   do_fsync+0x38/0x70\n   __x64_sys_fsync+0x10/0x20\n   do_syscall_64+0x33/0x80\n   entry_SYSCALL_64_after_hwframe+0x44/0xae\n  RIP: 0033:0x7fa9142a55c3\n  Code: 8b 15 09 (...)\n  RSP: 002b:00007fff26278d48 EFLAGS: 00000246 ORIG_RAX: 000000000000004a\n  RAX: ffffffffffffffda RBX: 0000563c83cb4560 RCX: 00007fa9142a55c3\n  RDX: 00007fff26278cb0 RSI: 00007fff26278cb0 RDI: 0000000000000005\n  RBP: 0000000000000005 R08: 0000000000000001 R09: 00007fff26278d5c\n  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000340\n  R13: 00007fff26278de0 R14: 00007fff26278d96 R15: 0000563c83ca57c0\n  Modules linked in: btrfs dm_zero dm_snapshot dm_thin_pool (...)\n  ---[ end trace ee2f1b19327d791d ]---\n\nThe steps that lead to this crash are the following:\n\n1) We are at transaction N;\n\n2) We have two tasks with a transaction handle attached to transaction N.\n   Task A and Task B. Task B is doing an fsync;\n\n3) Task B is at btrfs_sync_log(), and has saved fs_info-\u003elog_root_tree\n   into a local variable named 'log_root_tree' at the top of\n   btrfs_sync_log(). Task B is about to call write_all_supers(), but\n   before that...\n\n4) Task A calls btrfs_commit_transaction(), and after it sets the\n   transaction state to TRANS_STATE_COMMIT_START, an error happens before\n   it w\n---truncated---","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 race between transaction aborts and fsyncs leading to use-after-free","id":"CVE-2021-46958","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":4,"next":{"headline":"spi: Fix use-after-free with devm_spi_alloc_*","id":"CVE-2021-46959"},"packages":[],"prev":{"headline":"riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe","id":"CVE-2021-46957"},"products":["Linux"],"published":"2024-02-27","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":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A race condition in the Linux kernel's Btrfs filesystem can lead to a use-after-free, potentially causing system crashes or arbitrary code execution.","url":"https://insights.sbomify.com/CVE-2021-46958/"}