AT_SECURE programs may load attacker-controlled code via $ORIGIN

{
  "id": "4266f0e330f613e1fca8a48f5558cbf5a7e5be17245250e7cbc74e2f8d91e48f",
  "url": "https://osv.dev/vulnerability/CVE-2026-86805",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "AT_SECURE programs may load attacker-controlled code via $ORIGIN",
    "summary": "A time-of-check to time-of-use (TOCTOU) race condition in the dynamic loader (ld.so) of the GNU C Library (glibc) versions 2.14 through 2.44 allows a local attacker to escalate privileges. When expanding $ORIGIN in DT_RPATH for setuid/setgid (AT_SECURE) programs, glibc validates the lexically normalized search path against the trusted directories but then opens the raw, un-normalized path. On systems where the Linux fs.protected_hardlinks sysctl is disabled, a local attacker who hard-links such a program into an attacker-controlled directory and wins a race to replace an intermediate path component with a symbolic link can direct the loader outside the trusted directory, causing it to load an attacker-controlled shared object and execute arbitrary code with the elevated privileges of the program. Exploitation requires an installed setuid or setgid binary whose DT_RPATH uses $ORIGIN followed by \"..\" traversal that normalizes into a trusted directory, and the ability to hard-link that binary and win the race by swapping a path component for a symbolic link. Major Linux-based OS distributions ship with fs.protected_hardlinks enabled by default and mitigate the vulnerability.",
    "evidence": "osv:CVE-2026-86805",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-86805",
      "aliases": [
        "CVE-2026-86805"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://sourceware.org/git/glibc.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "356f8bc660a154a07b03da7c536831da5c8f74fe"
                },
                {
                  "last_affected": "c3a3a9808ad3ab4a3336836833f83288b672ccbf"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2.14"
                      },
                      {
                        "last_affected": "2.44"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "glibc-2.44",
            "glibc-2.43.9000",
            "glibc-2.43",
            "glibc-2.42",
            "glibc-2.42.9000",
            "glibc-2.41.9000",
            "glibc-2.41",
            "glibc-2.40",
            "glibc-2.40.9000",
            "glibc-2.39.9000",
            "glibc-2.39",
            "glibc-2.38",
            "glibc-2.38.9000",
            "glibc-2.37",
            "glibc-2.37.9000",
            "glibc-2.36",
            "glibc-2.36.9000",
            "glibc-2.35",
            "glibc-2.35.9000",
            "glibc-2.34",
            "glibc-2.34.9000",
            "glibc-2.33",
            "glibc-2.33.9000",
            "glibc-2.32",
            "glibc-2.32.9000",
            "glibc-2.31",
            "glibc-2.31.9000",
            "changelog-ends-here",
            "glibc-2.30",
            "glibc-2.30.9000",
            "glibc-2.29",
            "glibc-2.29.9000",
            "glibc-2.28",
            "glibc-2.28.9000",
            "glibc-2.27",
            "glibc-2.27.9000",
            "glibc-2.26",
            "glibc-2.26.9000",
            "glibc-2.25",
            "glibc-2.25.90",
            "glibc-2.24",
            "glibc-2.24.90",
            "glibc-2.23",
            "glibc-2.23.90",
            "glibc-2.22",
            "glibc-2.22.90",
            "glibc-2.21",
            "glibc-2.21.90",
            "glibc-2.20",
            "glibc-2.20.90",
            "glibc-2.19",
            "glibc-2.19.90",
            "glibc-2.18",
            "glibc-2.18.90",
            "glibc-2.17",
            "glibc-2.17.90",
            "glibc-2.16.0",
            "glibc-2.16.90",
            "glibc-2.16-ports-merge",
            "glibc-2.16",
            "glibc-2.16-tps",
            "glibc-2.15",
            "glibc-2.14.9000",
            "glibc-2.14"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-86805.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:42.967604760Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86805.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-86805",
        "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0022",
        "https://sourceware.org/bugzilla/show_bug.cgi?id=34360"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-367"
        ],
        "cna_assigner": "glibc",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "2.14"
                  },
                  {
                    "fixed": "2.45"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/86xxx/CVE-2026-86805.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-86805",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510954,
  "published_at": "2026-09-22T15:55:17.117+00:00"
}