CVE-2011-2768

CVE-2011-2768 is a medium-severity vulnerability in Tor with a CVSS 2.0 base score of 5.8. 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-264.

Key facts

Description

Tor before 0.2.2.34, when configured as a client or bridge, sends a TLS certificate chain as part of an outgoing OR connection, which allows remote relays to bypass intended anonymity properties by reading this chain and then determining the set of entry guards that the client or bridge had selected.

Frequently asked questions

What is CVE-2011-2768?
Tor before 0.2.2.34, when configured as a client or bridge, sends a TLS certificate chain as part of an outgoing OR connection, which allows remote relays to bypass intended anonymity properties by reading this chain and then determining the set of entry guards that the client or bridge had selected.
How severe is CVE-2011-2768?
CVE-2011-2768 has a CVSS 2.0 base score of 5.8, rated medium severity.
Is CVE-2011-2768 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2768?
CVE-2011-2768 primarily affects Tor. In total, 229 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2768?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-2768 published?
CVE-2011-2768 was published on 2011-12-23 and last updated on 2026-06-16.

References

Affected products (229)

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