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.
CVE-2026-77638
HIGHPre-NVD 8.98.9—Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
Score 8.9 from GitHub Security Advisory (severity: HIGH) published 2026-08-20. a secondary CVSS source baseline 8.9; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
8.9EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.9Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.9
- EG Score
- 8.9(high)
- EG Risk
- 45(Track)EG Risk 45/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity89% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
August 20, 2026
Last Modified
August 20, 2026
References (1)
Vendor Advisories for CVE-2026-77638(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-21 08:39 UTCEG score recompute
- 2026-08-21 08:39 UTCGHSA enrichment
- 2026-08-20 21:22 UTCEG score recompute
- 2026-08-20 21:07 UTCEG score recompute
- 2026-08-20 21:06 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-77638?
CVE-2026-77638 is a high vulnerability published on August 20, 2026. 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.
When was CVE-2026-77638 disclosed?
CVE-2026-77638 was first published in the National Vulnerability Database on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-77638?
CVE-2026-77638 has a CVSS v3 base score of 8.9 (NVD).
How do I remediate CVE-2026-77638?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77638, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-77638
Is Your Infrastructure Affected by CVE-2026-77638?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.