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.

Published: 2011-12-23 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-4894 is rated Low Risk (33/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.25%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2011-4894

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.40% 0.25% -0.15%
2 2025-03-29 0.25% 0.40% +0.15%
3 2025-03-17 — 0.25% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-4894

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2011-4894

OS Trackers for CVE-2011-4894

vendor priority summary link
debian unimportant CVE-2011-4894 unimportant priority: Debian including 1 source packages (tor), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-4894
ubuntu low CVE-2011-4894 low priority: Ubuntu including 1 source packages (tor), 9 status rows across 9 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, upstream): not-affected 4, ignored 3, DNE 2. https://ubuntu.com/security/CVE-2011-4894

Affected software / configurations for CVE-2011-4894

Vendor Product Version Raw CPE
tor tor <= 0.2.2.33 cpe:2.3:a:tor:tor:*:*:*:*:*:*:*:*
tor tor 0.0.2 cpe:2.3:a:tor:tor:0.0.2:*:*:*:*:*:*:*
tor tor 0.0.3 cpe:2.3:a:tor:tor:0.0.3:*:*:*:*:*:*:*
tor tor 0.0.4 cpe:2.3:a:tor:tor:0.0.4:*:*:*:*:*:*:*
tor tor 0.0.5 cpe:2.3:a:tor:tor:0.0.5:*:*:*:*:*:*:*
tor tor 0.0.6 cpe:2.3:a:tor:tor:0.0.6:*:*:*:*:*:*:*
tor tor 0.0.6.1 cpe:2.3:a:tor:tor:0.0.6.1:*:*:*:*:*:*:*
tor tor 0.0.6.2 cpe:2.3:a:tor:tor:0.0.6.2:*:*:*:*:*:*:*
tor tor 0.0.7 cpe:2.3:a:tor:tor:0.0.7:*:*:*:*:*:*:*
tor tor 0.0.7.1 cpe:2.3:a:tor:tor:0.0.7.1:*:*:*:*:*:*:*
tor tor 0.0.7.2 cpe:2.3:a:tor:tor:0.0.7.2:*:*:*:*:*:*:*
tor tor 0.0.7.3 cpe:2.3:a:tor:tor:0.0.7.3:*:*:*:*:*:*:*
tor tor 0.0.8 cpe:2.3:a:tor:tor:0.0.8:*:*:*:*:*:*:*
tor tor 0.0.8.1 cpe:2.3:a:tor:tor:0.0.8.1:*:*:*:*:*:*:*
tor tor 0.0.9 cpe:2.3:a:tor:tor:0.0.9:*:*:*:*:*:*:*
tor tor 0.0.9.1 cpe:2.3:a:tor:tor:0.0.9.1:*:*:*:*:*:*:*
tor tor 0.0.9.2 cpe:2.3:a:tor:tor:0.0.9.2:*:*:*:*:*:*:*
tor tor 0.0.9.3 cpe:2.3:a:tor:tor:0.0.9.3:*:*:*:*:*:*:*
tor tor 0.0.9.4 cpe:2.3:a:tor:tor:0.0.9.4:*:*:*:*:*:*:*
tor tor 0.0.9.5 cpe:2.3:a:tor:tor:0.0.9.5:*:*:*:*:*:*:*
tor tor 0.0.9.6 cpe:2.3:a:tor:tor:0.0.9.6:*:*:*:*:*:*:*
tor tor 0.0.9.7 cpe:2.3:a:tor:tor:0.0.9.7:*:*:*:*:*:*:*
tor tor 0.0.9.8 cpe:2.3:a:tor:tor:0.0.9.8:*:*:*:*:*:*:*
tor tor 0.0.9.9 cpe:2.3:a:tor:tor:0.0.9.9:*:*:*:*:*:*:*
tor tor 0.0.9.10 cpe:2.3:a:tor:tor:0.0.9.10:*:*:*:*:*:*:*
tor tor 0.1.0.1 cpe:2.3:a:tor:tor:0.1.0.1:*:*:*:*:*:*:*
tor tor 0.1.0.2 cpe:2.3:a:tor:tor:0.1.0.2:*:*:*:*:*:*:*
tor tor 0.1.0.3 cpe:2.3:a:tor:tor:0.1.0.3:*:*:*:*:*:*:*
tor tor 0.1.0.4 cpe:2.3:a:tor:tor:0.1.0.4:*:*:*:*:*:*:*
tor tor 0.1.0.5 cpe:2.3:a:tor:tor:0.1.0.5:*:*:*:*:*:*:*
tor tor 0.1.0.6 cpe:2.3:a:tor:tor:0.1.0.6:*:*:*:*:*:*:*
tor tor 0.1.0.7 cpe:2.3:a:tor:tor:0.1.0.7:*:*:*:*:*:*:*
tor tor 0.1.0.8 cpe:2.3:a:tor:tor:0.1.0.8:*:*:*:*:*:*:*
tor tor 0.1.0.9 cpe:2.3:a:tor:tor:0.1.0.9:*:*:*:*:*:*:*
tor tor 0.1.0.10 cpe:2.3:a:tor:tor:0.1.0.10:*:*:*:*:*:*:*
tor tor 0.1.0.11 cpe:2.3:a:tor:tor:0.1.0.11:*:*:*:*:*:*:*
tor tor 0.1.0.12 cpe:2.3:a:tor:tor:0.1.0.12:*:*:*:*:*:*:*
tor tor 0.1.0.13 cpe:2.3:a:tor:tor:0.1.0.13:*:*:*:*:*:*:*
tor tor 0.1.0.14 cpe:2.3:a:tor:tor:0.1.0.14:*:*:*:*:*:*:*
tor tor 0.1.0.15 cpe:2.3:a:tor:tor:0.1.0.15:*:*:*:*:*:*:*
tor tor 0.1.0.16 cpe:2.3:a:tor:tor:0.1.0.16:*:*:*:*:*:*:*
tor tor 0.1.0.17 cpe:2.3:a:tor:tor:0.1.0.17:*:*:*:*:*:*:*
tor tor 0.1.0.18 cpe:2.3:a:tor:tor:0.1.0.18:*:*:*:*:*:*:*
tor tor 0.1.0.19 cpe:2.3:a:tor:tor:0.1.0.19:*:*:*:*:*:*:*
tor tor 0.1.1 cpe:2.3:a:tor:tor:0.1.1:*:*:*:*:*:*:*
tor tor 0.1.1.1 cpe:2.3:a:tor:tor:0.1.1.1:*:*:*:*:*:*:*
tor tor 0.1.1.1 cpe:2.3:a:tor:tor:0.1.1.1:alpha:*:*:*:*:*:*
tor tor 0.1.1.2 cpe:2.3:a:tor:tor:0.1.1.2:*:*:*:*:*:*:*
tor tor 0.1.1.2 cpe:2.3:a:tor:tor:0.1.1.2:alpha:*:*:*:*:*:*
tor tor 0.1.1.3 cpe:2.3:a:tor:tor:0.1.1.3:*:*:*:*:*:*:*
tor tor 0.1.1.3 cpe:2.3:a:tor:tor:0.1.1.3:alpha:*:*:*:*:*:*
tor tor 0.1.1.4 cpe:2.3:a:tor:tor:0.1.1.4:*:*:*:*:*:*:*
tor tor 0.1.1.4 cpe:2.3:a:tor:tor:0.1.1.4:alpha:*:*:*:*:*:*
tor tor 0.1.1.5 cpe:2.3:a:tor:tor:0.1.1.5:*:*:*:*:*:*:*
tor tor 0.1.1.5 cpe:2.3:a:tor:tor:0.1.1.5:alpha:*:*:*:*:*:*
tor tor 0.1.1.6 cpe:2.3:a:tor:tor:0.1.1.6:*:*:*:*:*:*:*
tor tor 0.1.1.6 cpe:2.3:a:tor:tor:0.1.1.6:alpha:*:*:*:*:*:*
tor tor 0.1.1.7 cpe:2.3:a:tor:tor:0.1.1.7:*:*:*:*:*:*:*
tor tor 0.1.1.7 cpe:2.3:a:tor:tor:0.1.1.7:alpha:*:*:*:*:*:*
tor tor 0.1.1.8 cpe:2.3:a:tor:tor:0.1.1.8:*:*:*:*:*:*:*
tor tor 0.1.1.8 cpe:2.3:a:tor:tor:0.1.1.8:alpha:*:*:*:*:*:*
tor tor 0.1.1.9 cpe:2.3:a:tor:tor:0.1.1.9:*:*:*:*:*:*:*
tor tor 0.1.1.9 cpe:2.3:a:tor:tor:0.1.1.9:alpha:*:*:*:*:*:*
tor tor 0.1.1.10 cpe:2.3:a:tor:tor:0.1.1.10:*:*:*:*:*:*:*
tor tor 0.1.1.10 cpe:2.3:a:tor:tor:0.1.1.10:alpha:*:*:*:*:*:*
tor tor 0.1.1.11 cpe:2.3:a:tor:tor:0.1.1.11:*:*:*:*:*:*:*
tor tor 0.1.1.12 cpe:2.3:a:tor:tor:0.1.1.12:*:*:*:*:*:*:*
tor tor 0.1.1.13 cpe:2.3:a:tor:tor:0.1.1.13:*:*:*:*:*:*:*
tor tor 0.1.1.14 cpe:2.3:a:tor:tor:0.1.1.14:*:*:*:*:*:*:*
tor tor 0.1.1.15 cpe:2.3:a:tor:tor:0.1.1.15:*:*:*:*:*:*:*
tor tor 0.1.1.16 cpe:2.3:a:tor:tor:0.1.1.16:*:*:*:*:*:*:*
tor tor 0.1.1.17 cpe:2.3:a:tor:tor:0.1.1.17:*:*:*:*:*:*:*
tor tor 0.1.1.18 cpe:2.3:a:tor:tor:0.1.1.18:*:*:*:*:*:*:*
tor tor 0.1.1.19 cpe:2.3:a:tor:tor:0.1.1.19:*:*:*:*:*:*:*
tor tor 0.1.1.20 cpe:2.3:a:tor:tor:0.1.1.20:*:*:*:*:*:*:*
tor tor 0.1.1.21 cpe:2.3:a:tor:tor:0.1.1.21:*:*:*:*:*:*:*
tor tor 0.1.1.22 cpe:2.3:a:tor:tor:0.1.1.22:*:*:*:*:*:*:*
tor tor 0.1.1.23 cpe:2.3:a:tor:tor:0.1.1.23:*:*:*:*:*:*:*
tor tor 0.1.1.25 cpe:2.3:a:tor:tor:0.1.1.25:*:*:*:*:*:*:*
tor tor 0.1.1.26 cpe:2.3:a:tor:tor:0.1.1.26:*:*:*:*:*:*:*

References for CVE-2011-4894

cvelogic Threat Intelligence