CVE-2026-89905

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: LoongArch: BPF: Move arena register slot below TCC context Currently, the stack layout places the optional arena register slot above the tail call counter context. When arena_vm_start is dynamically enabled, it shifts the relative offset of the tcc_ptr slot within the stack frame, causing hardcoded tracking macros to mismatch and leading to memory misalignment or corruption potentially. To fix this, move the arena register save and restore sequences below the tail call counter context slots in both build_prologue() and the epilogue. Update __build_epilogue() to insert a proper offset decrement to safely skip the unneeded tcc_ptr reading block while accurately aligning with the relocated arena slot at the very bottom. With this patch, the tcc_ptr slot is always positioned at a fixed distance directly underneath the base callee-saved registers that is independent of whether the arena features are on.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-16 11:16:59.483000

Last modified

2026-10-19 09:18:35.907000

View original CVE JSON

{
  "id": "CVE-2026-89905",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-16T11:16:59.483",
  "lastModified": "2026-10-19T09:18:35.907",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: BPF: Move arena register slot below TCC context\n\nCurrently, the stack layout places the optional arena register slot\nabove the tail call counter context. When arena_vm_start is dynamically\nenabled, it shifts the relative offset of the tcc_ptr slot within the\nstack frame, causing hardcoded tracking macros to mismatch and leading\nto memory misalignment or corruption potentially.\n\nTo fix this, move the arena register save and restore sequences below\nthe tail call counter context slots in both build_prologue() and the\nepilogue.\n\nUpdate __build_epilogue() to insert a proper offset decrement to safely\nskip the unneeded tcc_ptr reading block while accurately aligning with\nthe relocated arena slot at the very bottom.\n\nWith this patch, the tcc_ptr slot is always positioned at a fixed\ndistance directly underneath the base callee-saved registers that is\nindependent of whether the arena features are on."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "arch/loongarch/net/bpf_jit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "ef54c517a9376b188da06b5e1ed556129c4280be",
              "lessThan": "f0e4d069cb47cf4f8dc4f6bc104e0671155aa3b9",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ef54c517a9376b188da06b5e1ed556129c4280be",
              "lessThan": "cd7e356b07a27e91394838cf3fb655862b519294",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "arch/loongarch/net/bpf_jit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "7.0",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "7.0",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.5",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/cd7e356b07a27e91394838cf3fb655862b519294",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f0e4d069cb47cf4f8dc4f6bc104e0671155aa3b9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}