{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2025-21820",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-21820",
    "idYear": 2025,
    "status": "PUBLISHED",
    "publishedAt": "2025-02-27T20:04:17.930Z",
    "updatedAt": "2026-05-11T21:07:09.122Z",
    "importedAt": "2026-10-24T01:57:29.455Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "tty: xilinx_uartps: split sysrq handling",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: xilinx_uartps: split sysrq handling\n\nlockdep detects the following circular locking dependency:\n\nCPU 0                      CPU 1\n========================== ============================\ncdns_uart_isr()            printk()\n  uart_port_lock(port)       console_lock()\n\t\t\t     cdns_uart_console_write()\n                               if (!port->sysrq)\n                                 uart_port_lock(port)\n  uart_handle_break()\n    port->sysrq = ...\n  uart_handle_sysrq_char()\n    printk()\n      console_lock()\n\nThe fixed commit attempts to avoid this situation by only taking the\nport lock in cdns_uart_console_write if port->sysrq unset. However, if\n(as shown above) cdns_uart_console_write runs before port->sysrq is set,\nthen it will try to take the port lock anyway. This may result in a\ndeadlock.\n\nFix this by splitting sysrq handling into two parts. We use the prepare\nhelper under the port lock and defer handling until we release the lock.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e22a97700901ba5e8bf8db68056a0d50f9440cae"
            },
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "de5bd24197bd9ee37ec1e379a3d882bbd15c5065"
            },
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "8ea0e7b3d7b8f2f0fc9db491ff22a0abe120801c"
            },
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "9b88a7c4584ba67267a051069b8abe44fc9595b2"
            },
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "4410dba9807a17a93f649a9f5870ceaf30a675a3"
            },
            {
              "version": "74ea66d4ca061a3cd4c0e924e51b60e924644852",
              "status": "affected",
              "versionType": "git",
              "lessThan": "b06f388994500297bb91be60ffaf6825ecfd2afe"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "4.6",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "4.6"
            },
            {
              "version": "5.15.179",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.129",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.78",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.14",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.13.3",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.13.*"
            },
            {
              "version": "6.14",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}