{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-63809", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-63809", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-07-19T12:02:11.905Z", "updatedAt": "2026-10-19T20:07:48.575Z", "importedAt": "2026-10-24T01:58:20.586Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "bpf: use kvfree() for replaced sysctl write buffer", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: use kvfree() for replaced sysctl write buffer\n\nproc_sys_call_handler() allocates its temporary sysctl buffer with\nkvzalloc() and passes it to __cgroup_bpf_run_filter_sysctl(). Since\nkvzalloc() may fall back to vmalloc() for large allocations, freeing\nthat buffer with kfree() is wrong and can corrupt memory.\n\nUse kvfree() to safely handle both kmalloc and kvzalloc()/vmalloc\nallocations.\n\nThe bug was first flagged by an experimental analysis tool we are\ndeveloping for kernel memory-management bugs while analyzing\nv6.13-rc1. The tool is still under development and is not yet publicly\navailable. Manual inspection confirms that the bug is still\npresent in v7.1-rc5.\n\nReproduced the bug based on v7.1-rc4 in a QEMU x86_64 guest booted with\nKASAN and CONFIG_FAILSLAB enabled. To exercise the replacement path, the\ntest tree also included the accompanying fix for the stale ret == 1\ncheck in __cgroup_bpf_run_filter_sysctl(). The reproducer confines\nfailslab injections to the proc_sys_call_handler() range, uses\nstacktrace-depth=32, and injects fail-nth=1 while writing 8191 bytes to\n/proc/sys/kernel/domainname from a task in the target cgroup. Under\nthat setup, fail-nth=1 triggered the fault:\n\n BUG: unable to handle page fault for address: ffffeb0200024d48\n #PF: supervisor read access in kernel mode\n #PF: error_code(0x0000) - not-present page\n PGD 0 P4D 0\n Oops: Oops: 0000 SMP KASAN NOPTI\n CPU: 2 UID: 0 PID: 209 Comm: repro_proc_sys_ Not tainted 7.1.0-rc4-00686-g97625979a5d4 PREEMPT(lazy)\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014\n RIP: 0010:kfree+0x6e/0x510\n ...\n Call Trace:\n \n ? __cgroup_bpf_run_filter_sysctl+0x626/0xc30\n __cgroup_bpf_run_filter_sysctl+0x74d/0xc30\n ? __pfx___cgroup_bpf_run_filter_sysctl+0x10/0x10\n ? srso_return_thunk+0x5/0x5f\n ? __kvmalloc_node_noprof+0x345/0x870\n ? proc_sys_call_handler+0x250/0x480\n ? srso_return_thunk+0x5/0x5f\n proc_sys_call_handler+0x3a2/0x480\n ? __pfx_proc_sys_call_handler+0x10/0x10\n ? srso_return_thunk+0x5/0x5f\n ? selinux_file_permission+0x39f/0x500\n ? srso_return_thunk+0x5/0x5f\n ? lock_is_held_type+0x9e/0x120\n vfs_write+0x98e/0x1000\n ...\n \n\nWith this fix applied on top of the same test setup, rerunning the\nreproducer with fail-nth=1 yields no corresponding Oops reports.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "b7925acd82926ebbf94a0f0783a3961f4e558856", "status": "affected", "versionType": "git", "lessThan": "d0a81ed5ff5d0f9c3f63a4f9e5a4642c363ecd3e" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "77355ef7a9f6b0d2bdf65be3b37f2c1f365e20d2" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "e1d1e203a6000804c5d3b8a4aa4e52303c0c7ab2" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "81fc9a13acae99966232f0e055eb2e445263b89a" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "838fe9c28121777c59a9406710a68fcf77bb8017" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "65bd0c0afb0e1bf3287458e342429b069624f7d4" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "70df4de46577fab5e25418f014583155a147c902" }, { "version": "4508943794efdd94171549c0bd52810e2f4ad9fe", "status": "affected", "versionType": "git", "lessThan": "4c21b5927d4364bfe7365f2700da5fea0ed0d004" }, { "version": "66258ab303588936ee1ee0794d9a271be24f73cb", "status": "affected", "versionType": "git" }, { "version": "5.10.20", "status": "affected", "versionType": "semver", "lessThan": "5.10.260" }, { "version": "5.11.3", "status": "affected", "versionType": "semver", "lessThan": "5.12" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.12", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.12" }, { "version": "5.10.260", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.211", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.177", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.144", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.95", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.38", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.3", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }