CVE-2026-77638 (GCVE-0-2026-77638)

Vulnerability from cvelistv5 – Published: 2026-08-20 20:52 – Updated: 2026-08-20 20:52
VLAI
Summary
Tor before 0.4.9.11 is prone to a race condition where in just the right circumstances a rendezvous point could man-in-the-middle (impersonate) the onion service that the client was trying to reach.
CWE
  • CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Impacted products
Vendor Product Version CPE status
torproject Tor Affected: 0.3.5.3-alpha , < 0.4.9.11 (custom)
    cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
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Show details on NVD website

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            "confidentialityImpact": "HIGH",
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              "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
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        "dateUpdated": "2026-08-20T20:52:29.708Z",
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    "datePublished": "2026-08-20T20:52:29.708Z",
    "dateReserved": "2026-08-20T20:52:29.384Z",
    "dateUpdated": "2026-08-20T20:52:29.708Z",
    "state": "PUBLISHED"
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  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-77638\",\"sourceIdentifier\":\"cve@mitre.org\",\"published\":\"2026-08-20T21:17:11.097\",\"lastModified\":\"2026-08-20T21:17:11.097\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Tor before 0.4.9.11 is prone to a race condition where in just the right circumstances a rendezvous point could man-in-the-middle (impersonate) the onion service that the client was trying to reach.\"}],\"affected\":[{\"source\":\"cve@mitre.org\",\"affectedData\":[{\"vendor\":\"torproject\",\"product\":\"Tor\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"0.3.5.3-alpha\",\"lessThan\":\"0.4.9.11\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"cve@mitre.org\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L\",\"baseScore\":8.9,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":2.2,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"cve@mitre.org\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"references\":[{\"url\":\"https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.11/ChangeLog\",\"source\":\"cve@mitre.org\"}]}}"
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

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