CVE-2011-2778

Multiple heap-based buffer overflows in Tor before 0.2.2.35 allow remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code by (1) establishing a SOCKS connection to SocksPort or (2) leveraging a SOCKS proxy configuration.

Published: 2011-12-23 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2011-2778 is rated Moderate Risk (61.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.82%). Mandatory action: Review affected assets and schedule remediation.

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-2011-2778

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 2026-06-15 3.51% 3.82% +0.32%
2 2026-01-27 4.52% 3.51% -1.02%
3 2025-11-13 4.52%

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-2778

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.6 2.0 HIGH
AV:N/AC:H/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
4.9 10.0 [email protected]

Weakness enumeration for CVE-2011-2778

OS Trackers for CVE-2011-2778

vendor priority summary link
debian not yet assigned CVE-2011-2778 not yet assigned 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-2011-2778
gentoo normal CVE-2011-2778: 1 GLSA(s) (201201-12), 1 atom(s) (net-misc/tor); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2011-2778
ubuntu medium CVE-2011-2778 medium 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-2011-2778

Affected software / configurations for CVE-2011-2778

Vendor Product Version Raw CPE
tor tor <= 0.2.2.34 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-2011-2778

cvelogic Threat Intelligence