In the Linux kernel, the following vulnerability has been resolved:
keys: Fix linking a duplicate key to a keyring's assoc_array
When making a DNS query inside the kernel using dns_query(), the request code can in rare cases end up creating a duplicate index key in the assoc_array of the destination keyring. It is eventually found by a BUG_ON() check in the assoc_array implementation and results in a crash.
Example report: [2158499.700025] kernel BUG at ../lib/assoc_array.c:652! [2158499.700039] invalid opcode: 0000 [#1] SMP PTI [2158499.700065] CPU: 3 PID: 31985 Comm: kworker/3:1 Kdump: loaded Not tainted 5.3.18-150300.59.90-default #1 SLE15-SP3 [2158499.700096] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 [2158499.700351] Workqueue: cifsiod cifs_resolve_server [cifs] [2158499.700380] RIP: 0010:assoc_array_insert+0x85f/0xa40 [2158499.700401] Code: ff 74 2b 48 8b 3b 49 8b 45 18 4c 89 e6 48 83 e7 fe e8 95 ec 74 00 3b 45 88 7d db 85 c0 79 d4 0f 0b 0f 0b 0f 0b e8 41 f2 be ff <0f> 0b 0f 0b 81 7d 88 ff ff ff 7f 4c 89 eb 4c 8b ad 58 ff ff ff 0f [2158499.700448] RSP: 0018:ffffc0bd6187faf0 EFLAGS: 00010282 [2158499.700470] RAX: ffff9f1ea7da2fe8 RBX: ffff9f1ea7da2fc1 RCX: 0000000000000005 [2158499.700492] RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000000 [2158499.700515] RBP: ffffc0bd6187fbb0 R08: ffff9f185faf1100 R09: 0000000000000000 [2158499.700538] R10: ffff9f1ea7da2cc0 R11: 000000005ed8cec8 R12: ffffc0bd6187fc28 [2158499.700561] R13: ffff9f15feb8d000 R14: ffff9f1ea7da2fc0 R15: ffff9f168dc0d740 [2158499.700585] FS: 0000000000000000(0000) GS:ffff9f185fac0000(0000) knlGS:0000000000000000 [2158499.700610] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2158499.700630] CR2: 00007fdd94fca238 CR3: 0000000809d8c006 CR4: 00000000003706e0 [2158499.700702] Call Trace: [2158499.700741] ? key_alloc+0x447/0x4b0 [2158499.700768] ? __key_link_begin+0x43/0xa0 [2158499.700790] __key_link_begin+0x43/0xa0 [2158499.700814] request_key_and_link+0x2c7/0x730 [2158499.700847] ? dns_resolver_read+0x20/0x20 [dns_resolver] [2158499.700873] ? key_default_cmp+0x20/0x20 [2158499.700898] request_key_tag+0x43/0xa0 [2158499.700926] dns_query+0x114/0x2ca [dns_resolver] [2158499.701127] dns_resolve_server_name_to_ip+0x194/0x310 [cifs] [2158499.701164] ? scnprintf+0x49/0x90 [2158499.701190] ? __switch_to_asm+0x40/0x70 [2158499.701211] ? __switch_to_asm+0x34/0x70 [2158499.701405] reconn_set_ipaddr_from_hostname+0x81/0x2a0 [cifs] [2158499.701603] cifs_resolve_server+0x4b/0xd0 [cifs] [2158499.701632] process_one_work+0x1f8/0x3e0 [2158499.701658] worker_thread+0x2d/0x3f0 [2158499.701682] ? process_one_work+0x3e0/0x3e0 [2158499.701703] kthread+0x10d/0x130 [2158499.701723] ? kthread_park+0xb0/0xb0 [2158499.701746] ret_from_fork+0x1f/0x40
The situation occurs as follows: * Some kernel facility invokes dns_query() to resolve a hostname, for example, "abcdef". The function registers its global DNS resolver cache as current->cred.thread_keyring and passes the query to request_key_net() -> request_key_tag() -> request_key_and_link(). * Function request_key_and_link() creates a keyring_search_context object. Its match_data.cmp method gets set via a call to type->match_preparse() (resolves to dns_resolver_match_preparse()) to dns_resolver_cmp(). * Function request_key_and_link() continues and invokes search_process_keyrings_rcu() which returns that a given key was not found. The control is then passed to request_key_and_link() -> construct_alloc_key(). * Concurrently to that, a second task similarly makes a DNS query for "abcdef." and its result gets inserted into the DNS resolver cache. * Back on the first task, function construct_alloc_key() first runs __key_link_begin() to determine an assoc_array_edit operation to insert a new key. Index keys in the array are compared exactly as-is, using keyring_compare_object(). The operation ---truncated---
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade bpftoolUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-toolsUpgrade kernel-livepatch-5.10.192-182.736Upgrade perfUpgrade kernelUpgrade kernel-tools-develUpgrade kernel-headersUpgrade perf-debuginfoUpgrade python-perf-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-debuginfoUpgrade kernel-livepatch-5.15.128-80.144Upgrade python-perfUpgrade kernel-debuginfoUpgrade kernel-develUpgrade bpftool-debuginfo | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade bpftoolUpgrade python3-perf-debuginfoUpgrade kernel-tools-develUpgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade perfUpgrade perf-debuginfoUpgrade kernel-develUpgrade bpftool-debuginfoUpgrade kernel-libbpf-develUpgrade kernel-debuginfoUpgrade kernel-libbpf-staticUpgrade kernel-headersUpgrade python3-perfUpgrade kernel-livepatch-6.1.49-69.116Upgrade kernel-libbpfUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-debuginfoUpgrade kernel | Feb 20, 2026 | Dec 30, 2025 |
| Debian | — | Upgrade linux | Dec 31, 2025 | Dec 31, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade kernel-toolsUpgrade bpftoolUpgrade kernel-abi-stablelistsUpgrade kernel-tools-libsUpgrade python3-perfUpgrade kernel | Mar 10, 2026 | Mar 10, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Dec 30, 2025 |
| Ubuntu | — | Upgrade linux-ibmUpgrade linux-gcp-5.4Upgrade linux-intel-iot-realtimeUpgrade linux-gcpUpgrade linux-bluefieldUpgrade linux-intel-iotgUpgrade linux-lowlatency-hwe-5.15Upgrade linux-ibm-5.15Upgrade linux-oracleUpgrade linux-fipsUpgrade linux-gcp-fipsUpgrade linux-xilinx-zynqmpUpgrade linux-nvidia-tegra-igxUpgrade linux-nvidiaUpgrade linux-awsUpgrade linux-gcp-5.15Upgrade linux-riscv-5.15Upgrade linux-nvidia-tegraUpgrade linux-realtimeUpgrade linux-nvidia-tegra-5.15Upgrade linux-aws-fipsUpgrade linux-kvmUpgrade linux-raspi-5.4Upgrade linux-hwe-5.4Upgrade linux-azure-5.15Upgrade linux-azure-5.4Upgrade linux-aws-5.15Upgrade linuxUpgrade linux-ibm-5.4Upgrade linux-lowlatencyUpgrade linux-intel-iotg-5.15Upgrade linux-gkeopUpgrade linux-raspiUpgrade linux-azureUpgrade linux-oracle-5.15Upgrade linux-oracle-5.4Upgrade linux-gkeUpgrade linux-aws-5.4Upgrade linux-hwe-5.15Upgrade linux-iotUpgrade linux-azure-fips | Jan 6, 2026 | Jan 2, 2026 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Dec 30, 2025 |
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