FKIE_CVE-2026-77640

Vulnerability from fkie_nvd - Published: 2026-08-20 21:17 - Updated: 2026-08-20 21:17
Severity
3.7 (Low) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Summary
tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip stream with done=1. A truncated stream never reaches Z_STREAM_END, causing zlib to return Z_BUF_ERROR with no input remaining, which buf_add_compress() mistook for a full output buffer and retried forever. Fixed by returning TOR_COMPRESS_ERROR in that case so the caller can abort cleanly. This is TROVE-2026-021.
References
cve@mitre.orghttps://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Tor",
          "vendor": "torproject",
          "versions": [
            {
              "lessThan": "0.4.9.9",
              "status": "affected",
              "version": "0.2.6.1-alpha",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "tor before 0.4.9.9 was prone to an infinite loop when decompressing a truncated zlib/gzip  stream with done=1. A truncated stream never reaches Z_STREAM_END,  causing zlib to return Z_BUF_ERROR with no input remaining, which  buf_add_compress() mistook for a full output buffer and retried forever. Fixed by returning TOR_COMPRESS_ERROR in that case so the caller can abort cleanly. This is TROVE-2026-021."
    }
  ],
  "id": "CVE-2026-77640",
  "lastModified": "2026-08-20T21:17:11.373",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 1.4,
        "source": "cve@mitre.org",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-20T21:17:11.373",
  "references": [
    {
      "source": "cve@mitre.org",
      "url": "https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1284"
        }
      ],
      "source": "cve@mitre.org",
      "type": "Primary"
    }
  ]
}



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