{"id":"CVE-2026-74479","state":"PUBLISHED","title":"net: pktgen: fix proc entry use-after-free","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: pktgen: fix proc entry use-after-free\n\npktgen_change_name() replaces pkt_dev->entry while holding t->if_lock.\npktgen_remove_device() removes the same entry before\n_rem_dev_from_if_list() takes that lock.\n\nThis allows the following interleaving:\n\n  CPU 0 (NETDEV_CHANGENAME)       CPU 1 (kpktgend)\n  if_lock(t)\n  proc_remove(pkt_dev->entry)\n                                  proc_remove(pkt_dev->entry)\n  pkt_dev->entry = proc_create_data(...)\n  if_unlock(t)\n\nThe kthread can pass the stale proc_dir_entry to proc_remove() after the\nrename path has freed it. A reproducer with a widened race window reports:\n\n  BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80\n  Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67\n  Call Trace:\n   proc_remove+0x78/0x80\n   pktgen_remove_device.isra.0+0x11c/0x4c0\n   pktgen_thread_worker+0x1214/0x6bc0\n   kthread+0x2c6/0x3b0\n  Allocated by task 95:\n   __proc_create+0x204/0x790\n   proc_create_data+0x72/0xe0\n   pktgen_thread_write+0xd61/0x1510\n  Freed by task 28:\n   kmem_cache_free+0xcb/0x3d0\n   proc_free_inode+0x5b/0x80\n   rcu_core+0x50a/0x1850\n  The buggy address belongs to the object at ffff8881478fea00\n   which belongs to the cache proc_dir_entry of size 192\n\nMove proc_remove() into the if_lock-protected list removal helper. Keep it\nbefore list_del_rcu() to preserve the ordering required by add_device().\nThe rename path must then finish replacing the entry before removal, or\nit observes that the device is no longer on the list.","publishedAt":"2026-08-15T12:27:13.172Z","updatedAt":"2026-10-16T19:05:48.651Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"82ed3db9269cb61e3c15bad2f6e221efce90e1e0","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"577443530cb592d5782a1f79847411a9363a65c8","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"f85a58340b91f225de3299dfa782c6414098077c","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"4ef801b838d85c0ea5852c50667f7344ce3b6cd0","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"b006a5404470bd3eb2aa0425fc447183032047ef","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"817ff6efdb7f484ea547218e11e17d8e43daa3b4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/pktgen.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.22","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.22","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.153","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.105","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/pktgen.c"]}],"references":["https://git.kernel.org/stable/c/82ed3db9269cb61e3c15bad2f6e221efce90e1e0","https://git.kernel.org/stable/c/d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4","https://git.kernel.org/stable/c/7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4","https://git.kernel.org/stable/c/577443530cb592d5782a1f79847411a9363a65c8","https://git.kernel.org/stable/c/f85a58340b91f225de3299dfa782c6414098077c","https://git.kernel.org/stable/c/4ef801b838d85c0ea5852c50667f7344ce3b6cd0","https://git.kernel.org/stable/c/b006a5404470bd3eb2aa0425fc447183032047ef","https://git.kernel.org/stable/c/817ff6efdb7f484ea547218e11e17d8e43daa3b4"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74479.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74479","state":"PUBLISHED","datePublished":"2026-08-15T12:27:13.172Z","dateUpdated":"2026-10-16T19:05:48.651Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.904Z"},"containers":{"cna":{"title":"net: pktgen: fix proc entry use-after-free","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: pktgen: fix proc entry use-after-free\n\npktgen_change_name() replaces pkt_dev->entry while holding t->if_lock.\npktgen_remove_device() removes the same entry before\n_rem_dev_from_if_list() takes that lock.\n\nThis allows the following interleaving:\n\n  CPU 0 (NETDEV_CHANGENAME)       CPU 1 (kpktgend)\n  if_lock(t)\n  proc_remove(pkt_dev->entry)\n                                  proc_remove(pkt_dev->entry)\n  pkt_dev->entry = proc_create_data(...)\n  if_unlock(t)\n\nThe kthread can pass the stale proc_dir_entry to proc_remove() after the\nrename path has freed it. A reproducer with a widened race window reports:\n\n  BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80\n  Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67\n  Call Trace:\n   proc_remove+0x78/0x80\n   pktgen_remove_device.isra.0+0x11c/0x4c0\n   pktgen_thread_worker+0x1214/0x6bc0\n   kthread+0x2c6/0x3b0\n  Allocated by task 95:\n   __proc_create+0x204/0x790\n   proc_create_data+0x72/0xe0\n   pktgen_thread_write+0xd61/0x1510\n  Freed by task 28:\n   kmem_cache_free+0xcb/0x3d0\n   proc_free_inode+0x5b/0x80\n   rcu_core+0x50a/0x1850\n  The buggy address belongs to the object at ffff8881478fea00\n   which belongs to the cache proc_dir_entry of size 192\n\nMove proc_remove() into the if_lock-protected list removal helper. Keep it\nbefore list_del_rcu() to preserve the ordering required by add_device().\nThe rename path must then finish replacing the entry before removal, or\nit observes that the device is no longer on the list."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"82ed3db9269cb61e3c15bad2f6e221efce90e1e0","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"577443530cb592d5782a1f79847411a9363a65c8","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"f85a58340b91f225de3299dfa782c6414098077c","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"4ef801b838d85c0ea5852c50667f7344ce3b6cd0","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"b006a5404470bd3eb2aa0425fc447183032047ef","versionType":"git"},{"version":"39df232f1a9ba48d41c68ee7d4046756e709cf91","status":"affected","lessThan":"817ff6efdb7f484ea547218e11e17d8e43daa3b4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/pktgen.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.22","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.22","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.153","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.105","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/pktgen.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/82ed3db9269cb61e3c15bad2f6e221efce90e1e0"},{"url":"https://git.kernel.org/stable/c/d1cc9797cf8f7aeb87e7ad01b748c6a960a819e4"},{"url":"https://git.kernel.org/stable/c/7991c7cff8b8622cddb3d8dee07dbe74aa4cbec4"},{"url":"https://git.kernel.org/stable/c/577443530cb592d5782a1f79847411a9363a65c8"},{"url":"https://git.kernel.org/stable/c/f85a58340b91f225de3299dfa782c6414098077c"},{"url":"https://git.kernel.org/stable/c/4ef801b838d85c0ea5852c50667f7344ce3b6cd0"},{"url":"https://git.kernel.org/stable/c/b006a5404470bd3eb2aa0425fc447183032047ef"},{"url":"https://git.kernel.org/stable/c/817ff6efdb7f484ea547218e11e17d8e43daa3b4"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires local access to /proc/net/pktgen procfs writes and a SIOCSIFNAME/ip-link rename of a pktgen-bound netdev; pktgen is configured only via local proc and ioctl paths, not via remote network packets.\nAC:L - The UAF is a race between pktgen_change_name() on NETDEV_CHANGENAME and pktgen_remove_device() in kpktgend; an attacker controls both sides concurrently via rem_device_all/unregister and interface rename, so success does not depend on uncontrollable timing.\nPR:L - Triggering rename needs ns_capable(CAP_NET_ADMIN) and pktgen proc writes are mode 0600; CAP_NET_ADMIN is obtainable by an unprivileged user via user/network namespaces (unshare -Urn), so real init-namespace root is not required.\nUI:N - No victim interaction is required; the attacker drives pktgen device add/remove and netdev rename/unregister directly through local proc writes and netlink/ioctl without needing another user to act.\nS:U - Impact is kernel slab corruption and potential privilege escalation within the same kernel security domain; it does not inherently cross VM, container, or IOMMU boundaries without additional unrelated primitives.\nC:H - The bug is a slab use-after-free of a proc_dir_entry in proc_remove(); KASAN shows reads of freed 192-byte objects, and UAF on proc metadata can be turned into arbitrary kernel memory disclosure via heap grooming.\nI:H - Corrupting or reusing the freed proc_dir_entry during proc_remove()/procfs teardown can enable attacker-controlled writes and control-flow hijack in kernel context, not merely a benign NULL dereference crash.\nA:H - Concurrent rename and removal causes proc_remove() to dereference a freed proc_dir_entry, producing KASAN slab-use-after-free and kernel oops/panic; even without full exploit development, the UAF reliably threatens system availability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-23T12:47:23.408Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"5.10.266"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"5.15.217"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"6.6.153"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"6.12.105"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.22","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74479","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:57:37.706862Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:05:48.651Z"}}]}}}