CVE-2011-4894

CVE-2011-4894 is a medium-severity vulnerability in Tor with a CVSS 2.0 base score of 4.3. 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-200.

Key facts

Description

Tor before 0.2.2.34, when configured as a bridge, uses direct DirPort access instead of a Tor TLS connection for a directory fetch, which makes it easier for remote attackers to enumerate bridges by observing DirPort connections.

Frequently asked questions

What is CVE-2011-4894?
Tor before 0.2.2.34, when configured as a bridge, uses direct DirPort access instead of a Tor TLS connection for a directory fetch, which makes it easier for remote attackers to enumerate bridges by observing DirPort connections.
How severe is CVE-2011-4894?
CVE-2011-4894 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2011-4894 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-4894?
CVE-2011-4894 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-2011-4894?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-4894 published?
CVE-2011-4894 was published on 2011-12-23 and last updated on 2026-06-16.

References

Affected products (229)

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