{ "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-2021-47222", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47222", "idYear": 2021, "status": "PUBLISHED", "publishedAt": "2024-05-21T14:19:28.214Z", "updatedAt": "2026-08-05T08:46:47.766Z", "importedAt": "2026-10-24T01:56:36.661Z", "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": "net: bridge: fix vlan tunnel dst refcnt when egressing", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix vlan tunnel dst refcnt when egressing\n\nThe egress tunnel code uses dst_clone() and directly sets the result\nwhich is wrong because the entry might have 0 refcnt or be already deleted,\ncausing number of problems. It also triggers the WARN_ON() in dst_hold()[1]\nwhen a refcnt couldn't be taken. Fix it by using dst_hold_safe() and\nchecking if a reference was actually taken before setting the dst.\n\n[1] dmesg WARN_ON log and following refcnt errors\n WARNING: CPU: 5 PID: 38 at include/net/dst.h:230 br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]\n Modules linked in: 8021q garp mrp bridge stp llc bonding ipv6 virtio_net\n CPU: 5 PID: 38 Comm: ksoftirqd/5 Kdump: loaded Tainted: G W 5.13.0-rc3+ #360\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014\n RIP: 0010:br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge]\n Code: e8 85 bc 01 e1 45 84 f6 74 90 45 31 f6 85 db 48 c7 c7 a0 02 19 a0 41 0f 94 c6 31 c9 31 d2 44 89 f6 e8 64 bc 01 e1 85 db 75 02 <0f> 0b 31 c9 31 d2 44 89 f6 48 c7 c7 70 02 19 a0 e8 4b bc 01 e1 49\n RSP: 0018:ffff8881003d39e8 EFLAGS: 00010246\n RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000\n RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa01902a0\n RBP: ffff8881040c6700 R08: 0000000000000000 R09: 0000000000000001\n R10: 2ce93d0054fe0d00 R11: 54fe0d00000e0000 R12: ffff888109515000\n R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000401\n FS: 0000000000000000(0000) GS:ffff88822bf40000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f42ba70f030 CR3: 0000000109926000 CR4: 00000000000006e0\n Call Trace:\n br_handle_vlan+0xbc/0xca [bridge]\n __br_forward+0x23/0x164 [bridge]\n deliver_clone+0x41/0x48 [bridge]\n br_handle_frame_finish+0x36f/0x3aa [bridge]\n ? skb_dst+0x2e/0x38 [bridge]\n ? br_handle_ingress_vlan_tunnel+0x3e/0x1c8 [bridge]\n ? br_handle_frame_finish+0x3aa/0x3aa [bridge]\n br_handle_frame+0x2c3/0x377 [bridge]\n ? __skb_pull+0x33/0x51\n ? vlan_do_receive+0x4f/0x36a\n ? br_handle_frame_finish+0x3aa/0x3aa [bridge]\n __netif_receive_skb_core+0x539/0x7c6\n ? __list_del_entry_valid+0x16e/0x1c2\n __netif_receive_skb_list_core+0x6d/0xd6\n netif_receive_skb_list_internal+0x1d9/0x1fa\n gro_normal_list+0x22/0x3e\n dev_gro_receive+0x55b/0x600\n ? detach_buf_split+0x58/0x140\n napi_gro_receive+0x94/0x12e\n virtnet_poll+0x15d/0x315 [virtio_net]\n __napi_poll+0x2c/0x1c9\n net_rx_action+0xe6/0x1fb\n __do_softirq+0x115/0x2d8\n run_ksoftirqd+0x18/0x20\n smpboot_thread_fn+0x183/0x19c\n ? smpboot_unregister_percpu_thread+0x66/0x66\n kthread+0x10a/0x10f\n ? kthread_mod_delayed_work+0xb6/0xb6\n ret_from_fork+0x22/0x30\n ---[ end trace 49f61b07f775fd2b ]---\n dst_release: dst:00000000c02d677a refcnt:-1\n dst_release underflow", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "42020f7f37a90d24b9551f5f7eba3f7c7c102968" }, { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "84fc1c944e45ab317e2e70a0e7f76fa2a5e43b6e" }, { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "79855be6445b6592bddb7bd7167083ec8cdbd73f" }, { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "fc7fdd8c5c2ad2fe3e297698be9d4dbe4a4e0579" }, { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "25053a8404ba17ca48f5553d487afc1882e9f56c" }, { "version": "11538d039ac6efcf4f1a6c536e1b87cd3668a9fd", "status": "affected", "versionType": "git", "lessThan": "cfc579f9d89af4ada58c69b03bcaa4887840f3b3" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.11", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.11" }, { "version": "4.14.238", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.14.*" }, { "version": "4.19.196", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "4.19.*" }, { "version": "5.4.128", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.46", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.12.13", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.12.*" }, { "version": "5.13", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }