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Froxlor before 2.3.12 Privilege Escalation via SSH Key Sync

Type: advisorySources: OSV

Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race condition in the SSH key synchronization cron (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles). The containment/symlink validation performed by FileDir::makeCorrectDir()/makeCorrectFile() is done only at check time; the live filesystem path is re-resolved as root at write time (file_put_contents with FILE_APPEND|LOCK_EX, followed by chmod/chown/chgrp), with a database round-trip and file reads in between, and no path or file-descriptor pinning (no O_NOFOLLOW or openat2(RESOLVE_NO_SYMLINKS)). On installations where the non-default setting system.allow_customer_shell=1 grants customers local shell access, a customer can atomically swap their ~/.ssh directory for a symlink after the check and before the write, causing the root-run cron to append the customer's public key to /root/.ssh/authorized_keys and to chown /root/.ssh to the customer, resulting in full root compromise of the panel host. The cron re-runs on every interval, allowing unlimited attempts. This is a residual race that bypasses the check-time fix introduced for GHSA-mq5v-... . The issue is fixed in Froxlor 2.3.12.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-100713
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 18:45 UTC · Revision 1

Source evidence

Froxlor before 2.3.12 Privilege Escalation via SSH Key Sync

core-osv · Original source

Published 26 Sept 2026, 13:24 UTC

Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race condition in the SSH key synchronization cron (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles). The containment/symlink validation performed by FileDir::makeCorrectDir()/makeCorrectFile() is done only at check time; the live filesystem path is re-resolved as root at write time (file_put_contents with FILE_APPEND|LOCK_EX, followed by chmod/chown/chgrp), with a database round-trip and file reads in between, and no path or file-descriptor pinning (no O_NOFOLLOW or openat2(RESOLVE_NO_SYMLINKS)). On installations where the non-default setting system.allow_customer_shell=1 grants customers local shell access, a customer can atomically swap their ~/.ssh directory for a symlink after the check and before the write, causing the root-run cron to append the customer's public key to /root/.ssh/authorized_keys and to chown /root/.ssh to the customer, resulting in full root compromise of the panel host. The cron re-runs on every interval, allowing unlimited attempts. This is a residual race that bypasses the check-time fix introduced for GHSA-mq5v-... . The issue is fixed in Froxlor 2.3.12.

osv:CVE-2026-100713
Complete source record
{
  "id": "34f17a8c900648561d4b426ddaf76db8aaaed7442a9dcb6d697675d0ea316fdc",
  "url": "https://osv.dev/vulnerability/CVE-2026-100713",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Froxlor before 2.3.12 Privilege Escalation via SSH Key Sync",
    "summary": "Froxlor 2.3.10 and earlier contain a time-of-check time-of-use (TOCTOU) race condition in the SSH key synchronization cron (lib/Froxlor/Cron/System/SshKeys.php, SshKeys::generateFiles). The containment/symlink validation performed by FileDir::makeCorrectDir()/makeCorrectFile() is done only at check time; the live filesystem path is re-resolved as root at write time (file_put_contents with FILE_APPEND|LOCK_EX, followed by chmod/chown/chgrp), with a database round-trip and file reads in between, and no path or file-descriptor pinning (no O_NOFOLLOW or openat2(RESOLVE_NO_SYMLINKS)). On installations where the non-default setting system.allow_customer_shell=1 grants customers local shell access, a customer can atomically swap their ~/.ssh directory for a symlink after the check and before the write, causing the root-run cron to append the customer's public key to /root/.ssh/authorized_keys and to chown /root/.ssh to the customer, resulting in full root compromise of the panel host. The cron re-runs on every interval, allowing unlimited attempts. This is a residual race that bypasses the check-time fix introduced for GHSA-mq5v-... . The issue is fixed in Froxlor 2.3.12.",
    "evidence": "osv:CVE-2026-100713",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-100713",
      "aliases": [
        "CVE-2026-100713",
        "GHSA-927x-9jfh-mq42"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/froxlor/froxlor",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "143b6ee634a4b9c237437b4b1206c7b733b86d95"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.3.12"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.3.10"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.3.11",
            "2.3.10",
            "2.3.9",
            "2.3.8",
            "2.3.7",
            "2.3.6",
            "2.3.5",
            "2.3.4",
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            "2.1.0",
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            "2.1.0-rc2",
            "2.1.0-rc1",
            "2.1.0-beta2",
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            "2.0.24",
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            "2.0.22",
            "2.0.21",
            "2.0.20",
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            "2.0.18",
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            "2.0.16",
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            "2.0.5",
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            "2.0.1",
            "0.10.33",
            "0.10.32",
            "0.10.31",
            "0.10.30",
            "0.10.29.1",
            "0.10.29",
            "0.10.28",
            "0.10.27",
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            "0.10.23.1",
            "0.10.23",
            "0.10.22",
            "0.10.21",
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            "0.10.18",
            "0.10.17",
            "0.10.16",
            "0.10.15",
            "0.10.14",
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            "0.10.7",
            "0.10.6",
            "0.10.5",
            "0.10.4",
            "0.10.3",
            "0.10.2",
            "0.10.1",
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            "0.10.0-rc2",
            "0.10.0-rc1",
            "0.9.39.5",
            "0.9.39.4",
            "0.9.39.3",
            "0.9.39.2",
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            "0.9.38.2",
            "0.9.38.1",
            "0.9.38",
            "0.9.38-rc2",
            "0.9.38-rc1",
            "0.9.37",
            "0.9.37-rc1",
            "0.9.36",
            "0.9.35.1",
            "0.9.35",
            "0.9.35-rc1",
            "0.9.34.2",
            "0.9.34.1",
            "0.9.33-rc3",
            "0.9.33-rc2",
            "0.9.33-rc1",
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            "0.9.20",
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            "0.9.18.1",
            "0.9.18"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100713.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.708322697Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100713.json",
        "https://github.com/froxlor/froxlor/security/advisories/GHSA-927x-9jfh-mq42",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-100713",
        "https://www.vulncheck.com/advisories/froxlor-before-2.3.12-privilege-escalation-via-ssh-key-sync"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-367"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100713.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-100713",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 498534,
  "published_at": "2026-09-26T13:24:05.746+00:00"
}