CVE-2026-77639

{"id": "CVE-2026-77639", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-77639", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-21T19:51:09.028997Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "cve@mitre.org", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "torproject", "product": "Tor", "versions": [{"status": "affected", "version": "0.3.1.1-alpha", "lessThan": "0.4.9.9", "versionType": "custom"}], "defaultStatus": "unaffected"}]}], "published": "2026-08-20T21:17:11.233", "references": [{"url": "https://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog", "tags": ["Release Notes", "Vendor Advisory"], "source": "cve@mitre.org"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "cve@mitre.org", "description": [{"lang": "en", "value": "CWE-420"}]}], "descriptions": [{"lang": "en", "value": "Tor before 0.4.9.9 was prone to a\u00a0compression bomb bypass where an attacker could concatenate many gzip or zlib sub-streams, each just under the per-stream detection threshold, to avoid the compression bomb check entirely. This is TROVE-2026-022."}], "lastModified": "2026-09-08T18:33:36.520", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F8FF755D-D472-48A8-9F10-F64B625DD9C3", "versionEndExcluding": "0.4.9.9"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}