GCVE-1988-2026-0342

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "Discuz! X5.0 UC_KEY",
          "vendor": "unknown",
          "versions": [
            {
              "status": "affected",
              "version": "unknown"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Egidio Romano"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "-------------------------------------------------------------\nDiscuz! X5.0 (UC_KEY) Cross-Context Token Reuse Vulnerability\n-------------------------------------------------------------\n\n\n[-] Software Link:\n\nhttps://www.discuz.vip\n\n\n[-] Affected Versions:\n\nVersion X5.0, releases 20260320 through 20260501.\n\n\n[-] Vulnerability Description:\n\nThe vulnerable code is located within the /config/config_ucenter.php\nconfiguration file:\n\ndefine('UC_KEY', $_config['security']['authkey']);\n\nDiscuz! X5.0, when installed in \"standalone mode\" (such as by the default\nconfiguration), initializes the UC_KEY cryptographic constant by directly\ncopying the value of the global authkey setting.\n\nAs a result, the same cryptographic key is shared across multiple unrelated\napplication components, including UCenter integration and the database\nbackup/restore API exposed by the /api/db/dbbak.php script. This breaks\ncryptographic isolation and allows tokens produced in one context to be\naccepted as valid in another.\n\nSpecifically, the logging_ctl::logging_more() method — invoked during a\nlogin request when the lssubmit parameter is present — encrypts\nattacker-controlled input with the global authkey setting and reflects the\nresulting ciphertext back to the client, effectively acting as an\nencryption oracle. By injecting a crafted command payload through the\nusername parameter, an unauthenticated attacker can obtain a legitimately\nsigned token that bypasses the authorization check in /api/db/dbbak.php,\ngaining unauthenticated access to the database export and import\nfunctionality.\n\nNOTE: by abusing the database export and import functionality, an attacker\nmay be able to trigger a Race Condition that ultimately allows\nimpersonating any user, bypassing authentication. This can be exploited in\ncombination with other vulnerabilities (such as KIS-2026-11) to achieve\nunauthenticated Remote Code Execution.\n\n\n[-] Proof of Concept:\n\nhttps://karmainsecurity.com/pocs/discuz_rce.zip\n\n\n[-] Solution:\n\nUpgrade to release 20260510 or later.\n\n\n[-] Disclosure Timeline:\n\n[27/04/2026] - Vendor contacted through private messages on gitee.com, no\nresponse\n[27/04/2026] - Vendor contacted via e-mail at admin () discuz vip and\nsecurity () tencent com, no response\n[07/05/2026] - Opened issue IJLFUW on https://gitee.com/Discuz/DiscuzX\n[09/05/2026] - Vulnerability details shared within issue IJLFUW\n[09/05/2026] - Vulnerability fixed within commit\n9962dad52c4c6999dabaf91ecd70377c680ff3c6\n[10/05/2026] - New fixed version (Discuz_X5.0_20260510) was released\n[09/06/2026] - CVE identifier requested\n[09/06/2026] - CVE identifier assigned\n[13/06/2026] - Public disclosure at hackmeeting 0x1D\n[15/06/2026] - Publication of this advisory\n\n\n[-] CVE Reference:\n\nCVE-2026-49952 has been assigned to this vulnerability.\n\n\n[-] Credits:\n\nVulnerability discovered by Egidio Romano.\n\n\n[-] Original Advisory:\n\nhttps://karmainsecurity.com/KIS-2026-09\n\n\n[-] Technical write-up:\n\nhttps://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce\n_______________________________________________\nSent through the Full Disclosure mailing list\nhttps://nmap.org/mailman/listinfo/fulldisclosure\nWeb Archives & RSS: https://seclists.org/fulldisclosure/"
        }
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        "dateUpdated": "2026-09-11T07:55:56Z",
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            "technical-description",
            "exploit"
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          "url": "https://vuln.freearchive.org/archive/full-disclosure/2026/Jun/3"
        },
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            "technical-description"
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          "url": "https://seclists.org/fulldisclosure/2026/Jun/3"
        },
        {
          "url": "https://gitee.com/Discuz/DiscuzX"
        },
        {
          "url": "https://karmainsecurity.com/KIS-2026-09"
        },
        {
          "url": "https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce"
        },
        {
          "url": "https://karmainsecurity.com/pocs/discuz_rce.zip"
        },
        {
          "url": "https://nmap.org/mailman/listinfo/fulldisclosure"
        },
        {
          "url": "https://seclists.org/fulldisclosure/"
        },
        {
          "url": "https://www.discuz.vip"
        }
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      "source": {
        "defect": [
          "https://seclists.org/fulldisclosure/2026/Jun/3"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "[KIS-2026-09] Discuz! X5.0 (UC_KEY) Cross-Context Token Reuse Vulnerability",
      "x_gcve": [
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          "recordType": "analysis",
          "relationships": [
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              "destId": "CVE-2026-49952",
              "type": "related"
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            "sourcePublishedAt": "2026-06-15T18:42:12Z"
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    "datePublished": "2026-09-11T07:55:56Z",
    "dateUpdated": "2026-09-11T07:55:56Z",
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