CVE-2026-43407

/* * PoC Concept for CVE-2026-43407 * This code simulates the payload structure that triggers the overflow. */ #include <stdio.h> #include <stdint.h> int main() { // Simulate the vulnerable field read from network packet uint32_t malicious_payload_len = 0xFFFFFFFF; // Max unsigned int printf("[PoC] Sending CEPH_MSG_AUTH_REPLY with payload_len: %u\n", malicious_payload_len); // Vulnerability simulation: // The vulnerable code does: int len = malicious_payload_len; // This results in len = -1. int len = (int)malicious_payload_len; printf("[Vuln] Integer overflow occurred. len interpreted as: %d\n", len); // This negative length is then used in pointer arithmetic, // leading to pointer decrement and out-of-bounds read. printf("[Impact] Triggering slab-out-of-bounds access in kernel.\n"); return 0; }

{"cve": {"id": "CVE-2026-43407", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-08T15:16:52.250", "lastModified": "2026-05-11T08:16:13.410", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()\n\nThis patch fixes an out-of-bounds access in ceph_handle_auth_reply()\nthat can be triggered by a message of type CEPH_MSG_AUTH_REPLY. In\nceph_handle_auth_reply(), the value of the payload_len field of such a\nmessage is stored in a variable of type int. A value greater than\nINT_MAX leads to an integer overflow and is interpreted as a negative\nvalue. This leads to decrementing the pointer address by this value and\nsubsequently accessing it because ceph_decode_need() only checks that\nthe memory access does not exceed the end address of the allocation.\n\nThis patch fixes the issue by changing the data type of payload_len to\nu32. Additionally, the data type of result_msg_len is changed to u32,\nas it is also a variable holding a non-negative length.\n\nAlso, an additional layer of sanity checks is introduced, ensuring that\ndirectly after reading it from the message, payload_len and\nresult_msg_len are not greater than the overall segment length.\n\nBUG: KASAN: slab-out-of-bounds in ceph_handle_auth_reply+0x642/0x7a0 [libceph]\nRead of size 4 at addr ffff88811404df14 by task kworker/20:1/262\n\nCPU: 20 UID: 0 PID: 262 Comm: kworker/20:1 Not tainted 6.19.2 #5 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nWorkqueue: ceph-msgr ceph_con_workfn [libceph]\nCall Trace:\n <TASK>\n dump_stack_lvl+0x76/0xa0\n print_report+0xd1/0x620\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? kasan_complete_mode_report_info+0x72/0x210\n kasan_report+0xe7/0x130\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n ? ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n __asan_report_load_n_noabort+0xf/0x20\n ceph_handle_auth_reply+0x642/0x7a0 [libceph]\n mon_dispatch+0x973/0x23d0 [libceph]\n ? apparmor_socket_recvmsg+0x6b/0xa0\n ? __pfx_mon_dispatch+0x10/0x10 [libceph]\n ? __kasan_check_write+0x14/0x30i\n ? mutex_unlock+0x7f/0xd0\n ? __pfx_mutex_unlock+0x10/0x10\n ? __pfx_do_recvmsg+0x10/0x10 [libceph]\n ceph_con_process_message+0x1f1/0x650 [libceph]\n process_message+0x1e/0x450 [libceph]\n ceph_con_v2_try_read+0x2e48/0x6c80 [libceph]\n ? __pfx_ceph_con_v2_try_read+0x10/0x10 [libceph]\n ? save_fpregs_to_fpstate+0xb0/0x230\n ? raw_spin_rq_unlock+0x17/0xa0\n ? finish_task_switch.isra.0+0x13b/0x760\n ? __switch_to+0x385/0xda0\n ? __kasan_check_write+0x14/0x30\n ? mutex_lock+0x8d/0xe0\n ? __pfx_mutex_lock+0x10/0x10\n ceph_con_workfn+0x248/0x10c0 [libceph]\n process_one_work+0x629/0xf80\n ? __kasan_check_write+0x14/0x30\n worker_thread+0x87f/0x1570\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? __pfx_try_to_wake_up+0x10/0x10\n ? kasan_print_address_stack_frame+0x1f7/0x280\n ? __pfx_worker_thread+0x10/0x10\n kthread+0x396/0x830\n ? __pfx__raw_spin_lock_irq+0x10/0x10\n ? __pfx_kthread+0x10/0x10\n ? __kasan_check_write+0x14/0x30\n ? recalc_sigpending+0x180/0x210\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x3f7/0x610\n ? __pfx_ret_from_fork+0x10/0x10\n ? __switch_to+0x385/0xda0\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\n[ idryomov: replace if statements with ceph_decode_need() for\n payload_len and result_msg_len ]"}], "metrics": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.2}]}, "references": [{"url": "https://git.kernel.org/stable/c/6cee34d6669fe176b4259131adb1a145c939b472", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/8bb87547e92dcf0928ed763c60e0ac8d733c3656", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9f9e2297f45fc2d2524eb104c289d69ddef95665", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/b282c43ed156ae15ea76748fc15cd5c39dc9ab72", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ea080b21092590122c3f971cf588932cdbf47847", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/ed024d2f4c79c0eb2464df0fb640610ac301f9a0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/edc678e5cd11730a2834b43071d8923f05bc334d", "source": "416baaa9-dc9f-4396-8d5f- ... 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