{
  "cveId": "CVE-2023-52761",
  "url": "https://patchblox.com/security/cve/CVE-2023-52761",
  "summary": "CVE-2023-52761 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-52761, released May 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  riscv: VMAP_STACK overflow detection thread-safe...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  riscv: VMAP_STACK overflow detection thread-safe  commit 31da94c25aea (\u0022riscv: add VMAP_STACK overflow detection\u0022) added support for CONFIG_VMAP_STACK. If overflow is detected, CPU switches to \u0060shadow_stack\u0060 temporarily before switching finally to per-cpu \u0060overflow_stack\u0060.  If two CPUs/harts are racing and end up in over flowing kernel stack, one or both will end up corrupting each other state because \u0060shadow_stack\u0060 is not per-cpu. This patch optimizes per-cpu overflow stack switch by directly picking per-cpu \u0060overflow_stack\u0060 and gets rid of \u0060shadow_stack\u0060.  Following are the changes in this patch   - Defines an asm macro to obtain per-cpu symbols in destination    register.  - In entry.S, when overflow is detected, per-cpu overflow stack is    located using per-cpu asm macro. Computing per-cpu symbol requires    a temporary register. x31 is saved away into CSR_SCRATCH    (CSR_SCRATCH is anyways zero since we\u0027re in kernel).  Please see Links for additional relevant disccussion and alternative solution.  Tested by \u0060echo EXHAUST_STACK \u003E /sys/kernel/debug/provoke-crash/DIRECT\u0060 Kernel crash log below   Insufficient stack space to handle exception!/debug/provoke-crash/DIRECT  Task stack:     [0xff20000010a98000..0xff20000010a9c000]  Overflow stack: [0xff600001f7d98370..0xff600001f7d99370]  CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34  Hardware name: riscv-virtio,qemu (DT)  epc : __memset\u002B0x60/0xfc   ra : recursive_loop\u002B0x48/0xc6 [lkdtm]  epc : ffffffff808de0e4 ra : ffffffff0163a752 sp : ff20000010a97e80   gp : ffffffff815c0330 tp : ff600000820ea280 t0 : ff20000010a97e88   t1 : 000000000000002e t2 : 3233206874706564 s0 : ff20000010a982b0   s1 : 0000000000000012 a0 : ff20000010a97e88 a1 : 0000000000000000   a2 : 0000000000000400 a3 : ff20000010a98288 a4 : 0000000000000000   a5 : 0000000000000000 a6 : fffffffffffe43f0 a7 : 00007fffffffffff   s2 : ff20000010a97e88 s3 : ffffffff01644680 s4 : ff20000010a9be90   s5 : ff600000842ba6c0 s6 : 00aaaaaac29e42b0 s7 : 00fffffff0aa3684   s8 : 00aaaaaac2978040 s9 : 0000000000000065 s10: 00ffffff8a7cad10   s11: 00ffffff8a76a4e0 t3 : ffffffff815dbaf4 t4 : ffffffff815dbaf4   t5 : ffffffff815dbab8 t6 : ff20000010a9bb48  status: 0000000200000120 badaddr: ff20000010a97e88 cause: 000000000000000f  Kernel panic - not syncing: Kernel stack overflow  CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34  Hardware name: riscv-virtio,qemu (DT)  Call Trace:  [\u003Cffffffff80006754\u003E] dump_backtrace\u002B0x30/0x38  [\u003Cffffffff808de798\u003E] show_stack\u002B0x40/0x4c  [\u003Cffffffff808ea2a8\u003E] dump_stack_lvl\u002B0x44/0x5c  [\u003Cffffffff808ea2d8\u003E] dump_stack\u002B0x18/0x20  [\u003Cffffffff808dec06\u003E] panic\u002B0x126/0x2fe  [\u003Cffffffff800065ea\u003E] walk_stackframe\u002B0x0/0xf0  [\u003Cffffffff0163a752\u003E] recursive_loop\u002B0x48/0xc6 [lkdtm]  SMP: stopping secondary CPUs  ---[ end Kernel panic - not syncing: Kernel stack overflow ]---",
  "published": "2024-05-21T16:15:15Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00267,
  "epssPercentile": 0.18928,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.5.13-1",
      "fix": "DEBIAN-CVE-2023-52761",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52761",
      "released": "2024-05-21T16:15:15Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.5.13-1",
      "fix": "DEBIAN-CVE-2023-52761",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2023-52761",
      "released": "2024-05-21T16:15:15Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-10T01:44:33Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}