CVE-2026-43407 (GCVE-0-2026-43407)
Vulnerability from cvelistv5
Published
2026-05-08 14:21
Modified
2026-08-05 12:27
Severity ?
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply() This patch fixes an out-of-bounds access in ceph_handle_auth_reply() that can be triggered by a message of type CEPH_MSG_AUTH_REPLY. In ceph_handle_auth_reply(), the value of the payload_len field of such a message is stored in a variable of type int. A value greater than INT_MAX leads to an integer overflow and is interpreted as a negative value. This leads to decrementing the pointer address by this value and subsequently accessing it because ceph_decode_need() only checks that the memory access does not exceed the end address of the allocation. This patch fixes the issue by changing the data type of payload_len to u32. Additionally, the data type of result_msg_len is changed to u32, as it is also a variable holding a non-negative length. Also, an additional layer of sanity checks is introduced, ensuring that directly after reading it from the message, payload_len and result_msg_len are not greater than the overall segment length. BUG: KASAN: slab-out-of-bounds in ceph_handle_auth_reply+0x642/0x7a0 [libceph] Read of size 4 at addr ffff88811404df14 by task kworker/20:1/262 CPU: 20 UID: 0 PID: 262 Comm: kworker/20:1 Not tainted 6.19.2 #5 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: ceph-msgr ceph_con_workfn [libceph] Call Trace: <TASK> dump_stack_lvl+0x76/0xa0 print_report+0xd1/0x620 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? kasan_complete_mode_report_info+0x72/0x210 kasan_report+0xe7/0x130 ? ceph_handle_auth_reply+0x642/0x7a0 [libceph] ? ceph_handle_auth_reply+0x642/0x7a0 [libceph] __asan_report_load_n_noabort+0xf/0x20 ceph_handle_auth_reply+0x642/0x7a0 [libceph] mon_dispatch+0x973/0x23d0 [libceph] ? apparmor_socket_recvmsg+0x6b/0xa0 ? __pfx_mon_dispatch+0x10/0x10 [libceph] ? __kasan_check_write+0x14/0x30i ? mutex_unlock+0x7f/0xd0 ? __pfx_mutex_unlock+0x10/0x10 ? __pfx_do_recvmsg+0x10/0x10 [libceph] ceph_con_process_message+0x1f1/0x650 [libceph] process_message+0x1e/0x450 [libceph] ceph_con_v2_try_read+0x2e48/0x6c80 [libceph] ? __pfx_ceph_con_v2_try_read+0x10/0x10 [libceph] ? save_fpregs_to_fpstate+0xb0/0x230 ? raw_spin_rq_unlock+0x17/0xa0 ? finish_task_switch.isra.0+0x13b/0x760 ? __switch_to+0x385/0xda0 ? __kasan_check_write+0x14/0x30 ? mutex_lock+0x8d/0xe0 ? __pfx_mutex_lock+0x10/0x10 ceph_con_workfn+0x248/0x10c0 [libceph] process_one_work+0x629/0xf80 ? __kasan_check_write+0x14/0x30 worker_thread+0x87f/0x1570 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __pfx_try_to_wake_up+0x10/0x10 ? kasan_print_address_stack_frame+0x1f7/0x280 ? __pfx_worker_thread+0x10/0x10 kthread+0x396/0x830 ? __pfx__raw_spin_lock_irq+0x10/0x10 ? __pfx_kthread+0x10/0x10 ? __kasan_check_write+0x14/0x30 ? recalc_sigpending+0x180/0x210 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x3f7/0x610 ? __pfx_ret_from_fork+0x10/0x10 ? __switch_to+0x385/0xda0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> [ idryomov: replace if statements with ceph_decode_need() for payload_len and result_msg_len ]
References
Impacted products
Vendor Product Version
Linux Linux Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
Version: 4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ceph/auth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "4e7a5dcd1bbab6560fbc8ada29a840e7a20ed7bc",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.34"
            },
            {
              "lessThan": "2.6.34",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "5.15.203",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.1.167",
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.6.130",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.18.19",
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                  "vulnerable": true
                },
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "2.6.34",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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 \u003cTASK\u003e\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 \u003c/TASK\u003e\n\n[ idryomov: replace if statements with ceph_decode_need() for\n  payload_len and result_msg_len ]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable `CEPH_MSG_AUTH_REPLY` is parsed from data received over a Ceph messenger TCP connection from a monitor peer. A malicious or compromised monitor, or an attacker in position to impersonate one, can supply the crafted network message remotely.\nAC:L - The trigger is a deterministic malformed length field in a single auth reply, with no race or unusual heap state required to reach the out-of-bounds read. The attacker controls the relevant message contents.\nPR:N - The vulnerable reply is processed by the kernel client from the network peer during monitor/auth session handling, before any attacker-controlled credentials are required on the target. No local account or target privileges are needed.\nUI:N - Once a Ceph client connects or reconnects to the monitor peer, the attacker can send the crafted reply without further victim action. This is server-to-client network input processing.\nS:U - The impact is within the Linux kernel/client security authority. It does not cross a hypervisor, IOMMU, or separate authorization scope boundary.\nC:H - The signed length overflow lets the attacker move the decode pointer before the message buffer and perform an out-of-bounds kernel memory read at an attacker-influenced offset. Although the immediate read is small, it is not confined to a fixed in-object field, so high confidentiality impact is the safer defensible choice.\nI:N - The bug is an out-of-bounds read caused by pointer underflow; the investigated path does not provide an out-of-bounds write or direct memory corruption primitive. The downstream auth handlers reject the inverted buffer range or ignore the payload.\nA:H - The commit includes a KASAN slab-out-of-bounds report in `ceph_handle_auth_reply()`, and attacker-controlled pointer underflow can fault or oops the kernel worker processing the connection. A malicious peer can repeat the malformed reply to disrupt affected clients."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:50.423Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ea080b21092590122c3f971cf588932cdbf47847"
        },
        {
          "url": "https://git.kernel.org/stable/c/edc678e5cd11730a2834b43071d8923f05bc334d"
        },
        {
          "url": "https://git.kernel.org/stable/c/6cee34d6669fe176b4259131adb1a145c939b472"
        },
        {
          "url": "https://git.kernel.org/stable/c/8bb87547e92dcf0928ed763c60e0ac8d733c3656"
        },
        {
          "url": "https://git.kernel.org/stable/c/ed024d2f4c79c0eb2464df0fb640610ac301f9a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/f9da5c1bbac5c8e33259fe00ed7347438fffa969"
        },
        {
          "url": "https://git.kernel.org/stable/c/9f9e2297f45fc2d2524eb104c289d69ddef95665"
        },
        {
          "url": "https://git.kernel.org/stable/c/b282c43ed156ae15ea76748fc15cd5c39dc9ab72"
        }
      ],
      "title": "libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43407",
    "datePublished": "2026-05-08T14:21:46.927Z",
    "dateReserved": "2026-05-01T14:12:56.008Z",
    "dateUpdated": "2026-08-05T12:27:50.423Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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