Tor Project prior 0.4.9.11 Rendezvous Point race condition

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
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CTI Interest Score
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9.2$5k-$25k0.47+

Summaryinfo

A vulnerability marked as very critical has been reported in Tor Project Tor. The impacted element is an unknown function of the component Rendezvous Point. Performing a manipulation results in race condition. This vulnerability was named CVE-2026-77638. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Tor Project Tor. It has been classified as very critical. This affects an unknown code of the component Rendezvous Point. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at gitlab.torproject.org. This vulnerability is uniquely identified as CVE-2026-77638 since 08/20/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/20/2026).

Upgrading to version 0.4.9.11 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Vendor

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.5
VulDB Meta Temp Score: 9.2

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.9
CNA Vector (MITRE): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Tor 0.4.9.11

Timelineinfo

08/20/2026 Advisory disclosed
08/20/2026 +0 days CVE reserved
08/20/2026 +0 days VulDB entry created
08/20/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: gitlab.torproject.org
Status: Confirmed

CVE: CVE-2026-77638 (🔒)
GCVE (CVE): GCVE-0-2026-77638
GCVE (VulDB): GCVE-100-393873

Entryinfo

Created: 08/20/2026 23:16
Changes: 08/20/2026 23:16 (63)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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