{"id":"AZL-104198","summary":"CVE-2026-97920 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Keep the entry count when the histogram stats allocation fails\n\nprint_entries() uses n_entries both as the number of sort entries and as\nits own return value, so the -ENOMEM it stores when the stats allocation\nfails overwrites the count that the cleanup still needs:\n\n\tn_entries = tracing_map_sort_entries(map, ...);\n\tif (n_entries \u003c 0)\n\t\treturn n_entries;\n\t...\n\t\t\tif (!stats) {\n\t\t\t\tn_entries = -ENOMEM;\n\t\t\t\tgoto out;\n\t\t\t}\n\t...\n out:\n\ttracing_map_destroy_sort_entries(sort_entries, n_entries);\n\ntracing_map_destroy_sort_entries() takes an unsigned int and loops up to\nit, so -ENOMEM arrives as 4294967284. It walks an array of at most\nmap-\u003emax_elts pointers and calls destroy_sort_entry(), which dereferences\nand frees, on whatever lies past the end.\n\nReading the hist file of a trigger with a .percent value, with that\nallocation forced to fail:\n\n  BUG: KASAN: vmalloc-out-of-bounds in tracing_map_destroy_sort_entries+0xa0/0xb0\n  Read of size 8 at addr ffffc90000045000 by task init/1\n   tracing_map_destroy_sort_entries+0xa0/0xb0\n   hist_show+0x6f7/0x1df0\n   seq_read_iter+0x2b8/0x1190\n   vfs_read+0x176/0xa40\n  The buggy address belongs to a 4-page vmalloc region starting at\n  ffffc90000041000 allocated at tracing_map_sort_entries+0x5c/0xd50\n\nA few pages further the fault is fatal. The registers at the oops confirm\nthe bound: the loop's end pointer less the array start, over the pointer\nsize, is 4294967284.\n\nReturn the error in a separate variable and leave n_entries holding the\ncount, the way tracing_map_sort_entries() does on its own error path.\n\nThe stats block is only entered for a value carrying .percent or .graph,\nwhich __create_val_field() has rejected since v6.3, so this cannot be\nreached in mainline as it stands. It becomes reachable again with\n\"tracing: hist: let values keep the percent and graph modifiers\", so it\nshould be applied first.","modified":"2026-09-26T14:16:11.137361127Z","published":"2026-09-25T11:17:19Z","upstream":["CVE-2026-97920"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97920"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-104198.json"}}],"schema_version":"1.9.0"}