{"cve":"CVE-2024-50301","nvd":{"published":"2024-11-19T02:16:32.230","modified":"2026-10-15T01:19:11.853","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsecurity/keys: fix slab-out-of-bounds in key_task_permission\n\nKASAN reports an out of bounds read:\nBUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36\nBUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline]\nBUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410\nsecurity/keys/permission.c:54\nRead of size 4 at addr ffff88813c3ab618 by task stress-ng/4362\n\nCPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15\nCall Trace:\n __dump_stack lib/dump_stack.c:82 [inline]\n dump_stack+0x107/0x167 lib/dump_stack.c:123\n print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400\n __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560\n kasan_report+0x3a/0x50 mm/kasan/report.c:585\n __kuid_val include/linux/uidgid.h:36 [inline]\n uid_eq include/linux/uidgid.h:63 [inline]\n key_task_permission+0x394/0x410 security/keys/permission.c:54\n search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793\n\nThis issue was also reported by syzbot.\n\nIt can be reproduced by following these steps(more details [1]):\n1. Obtain more than 32 inputs that have similar hashes, which ends with the\n   pattern '0xxxxxxxe6'.\n2. Reboot and add the keys obtained in step 1.\n\nThe reproducer demonstrates how this issue happened:\n1. In the search_nested_keyrings function, when it iterates through the\n   slots in a node(below tag ascend_to_node), if the slot pointer is meta\n   and node->back_pointer != NULL(it means a root), it will proceed to\n   descend_to_node. However, there is an exception. If node is the root,\n   and one of the slots points to a shortcut, it will be treated as a\n   keyring.\n2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function.\n   However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as\n   ASSOC_ARRAY_PTR_SUBTYPE_MASK.\n3. When 32 keys with the similar hashes are added to the tree, the ROOT\n   has keys with hashes that are not similar (e.g. slot 0) and it splits\n   NODE A without using a shortcut. When NODE A is filled with keys that\n   all hashes are xxe6, the keys are similar, NODE A will split with a\n   shortcut. Finally, it forms the tree as shown below, where slot 6 points\n   to a shortcut.\n\n                      NODE A\n              +------>+---+\n      ROOT    |       | 0 | xxe6\n      +---+   |       +---+\n xxxx | 0 | shortcut  :   : xxe6\n      +---+   |       +---+\n xxe6 :   :   |       |   | xxe6\n      +---+   |       +---+\n      | 6 |---+       :   : xxe6\n      +---+           +---+\n xxe6 :   :           | f | xxe6\n      +---+           +---+\n xxe6 | f |\n      +---+\n\n4. As mentioned above, If a slot(slot 6) of the root points to a shortcut,\n   it may be mistakenly transferred to a key*, leading to a read\n   out-of-bounds read.\n\nTo fix this issue, one should jump to descend_to_node if the ptr is a\nshortcut, regardless of whether the node is root or not.\n\n[1] https://lore.kernel.org/linux-kernel/1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com/\n\n[jarkko: tweaked the commit message a bit to have an appropriate closes\n tag.]","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","score":7.1},"cwes":["CWE-125"],"references":["https://git.kernel.org/stable/c/199c20fb7499c79557a075dc24e9a7dae7d9f1ce","https://git.kernel.org/stable/c/1e4332581cd4eed75aea77af6f66cdcdda8b49b9","https://git.kernel.org/stable/c/3e79ad156bedf2da0ab909a118d2cec6c9c22b79","https://git.kernel.org/stable/c/4a74da044ec9ec8679e6beccc4306b936b62873f","https://git.kernel.org/stable/c/4efb69a0e294ef201bcdf7ce3d6202cd0a545a5d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:57:34.731061660+00:00"},"epss":{"cve":"CVE-2024-50301","score":0.00283,"percentile":0.20606,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}