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          {
            "url": "http://www.openwall.com/lists/oss-security/2026/08/22/5"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
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              "name": "Punk::App::session"
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            }
          ],
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            {
              "lessThan": "0.18",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
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          ]
        }
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      "descriptions": [
        {
          "lang": "en",
          "value": "Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret.\n\nThe session keyword freezes its options onto the application as given: it does not require a secret, warn, or refuse to start when one is absent. The cookie read and the write-back both default that key to the empty string, so a declaration with no secret option, or with an undefined or empty one, signs and verifies with a zero-length HMAC-SHA256 key.\n\nAn attacker who knows the cookie format can then mint one offline carrying any contents the session holds, such as a user identifier or a role. Nothing marks the misconfiguration at runtime: cookies are well formed and sessions round-trip as expected."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1394",
              "description": "CWE-1394 Use of Default Cryptographic Key",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-22T13:35:58.346Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
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      "references": [
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://metacpan.org/release/LNATION/Punk-0.17/source/include/punk/punk_session.h"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://metacpan.org/release/LNATION/Punk-0.17/view/lib/Punk.pm"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/LNATION/Punk-0.18/source/Changes"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Punk 0.18 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret",
      "workarounds": [
        {
          "lang": "en",
          "value": "For deployments that cannot upgrade to 0.18, declare the session keyword with a non-empty secret. The secret keyword fails closed, so sourcing the key through it turns a missing configuration path or an unset environment variable into a startup error."
        }
      ],
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
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  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-75870",
    "datePublished": "2026-08-22T13:35:58.346Z",
    "dateReserved": "2026-08-18T11:59:49.642Z",
    "dateUpdated": "2026-08-22T19:07:10.053Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-75870\",\"sourceIdentifier\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"published\":\"2026-08-22T14:16:33.813\",\"lastModified\":\"2026-08-22T19:16:20.430\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Punk versions before 0.18 for Perl allow session cookie forgery via an empty default HMAC key when a session is declared without a secret.\\n\\nThe session keyword freezes its options onto the application as given: it does not require a secret, warn, or refuse to start when one is absent. The cookie read and the write-back both default that key to the empty string, so a declaration with no secret option, or with an undefined or empty one, signs and verifies with a zero-length HMAC-SHA256 key.\\n\\nAn attacker who knows the cookie format can then mint one offline carrying any contents the session holds, such as a user identifier or a role. Nothing marks the misconfiguration at runtime: cookies are well formed and sessions round-trip as expected.\"}],\"affected\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"affectedData\":[{\"defaultStatus\":\"unaffected\",\"collectionURL\":\"https://cpan.org/modules\",\"packageName\":\"Punk\",\"modules\":[\"Punk\"],\"programFiles\":[\"xs/app.xs\",\"include/punk/punk_session.h\"],\"programRoutines\":[{\"name\":\"Punk::App::session\"},{\"name\":\"ps_load\"},{\"name\":\"ps_writeback\"}],\"packageURL\":\"pkg:cpan/Punk\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"0.18\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{},\"weaknesses\":[{\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-1394\"}]}],\"references\":[{\"url\":\"https://metacpan.org/release/LNATION/Punk-0.17/source/include/punk/punk_session.h\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/LNATION/Punk-0.17/view/lib/Punk.pm\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"https://metacpan.org/release/LNATION/Punk-0.18/source/Changes\",\"source\":\"9b29abf9-4ab0-4765-b253-1875cd9b441e\"},{\"url\":\"http://www.openwall.com/lists/oss-security/2026/08/22/5\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}"
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