CVE-2026-77638
CVE-2026-77638 is a high-severity vulnerability in Torproject Tor with a CVSS 3.x base score of 8.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-362.
Key facts
- Severity: High (CVSS 3.x base score 8.9)
- EPSS exploit prediction: 0% (21st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-362
- Affected product: Torproject Tor
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-77638?
- 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.
- How severe is CVE-2026-77638?
- CVE-2026-77638 has a CVSS 3.x base score of 8.9, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
- Is CVE-2026-77638 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-77638?
- CVE-2026-77638 affects Torproject Tor. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-77638?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-77638 published?
- CVE-2026-77638 was published on 2026-08-20 and last updated on 2026-09-16.
References
Affected products (1)
- cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
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