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CVE-2011-0491

18
FAUCET Score

CVE-2011-0491 describes a denial-of-service vulnerability in the tor_realloc function of Tor versions prior to 0.2.1.29 and 0.2.2.21-alpha. This flaw, stemming from improper size validation during memory allocation, could allow remote attackers to crash the Tor daemon through unspecified vectors related to "underflow errors." With a CVSS score of 5.0 (AV:N/AC:L/Au:N/C:N/I:N/A:P), it indicates a low-complexity attack that can be launched remotely without authentication, leading to a partial availability impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 0.2.1.28CPE matchmatch criteria
cpe:2.3:a:tor:tor:*:*:*:*:*:*:*:*
0.0.2CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.0.2:*:*:*:*:*:*:*
0.0.2_pre13CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.0.2_pre13:*:*:*:*:*:*:*
0.0.2_pre14CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.0.2_pre14:*:*:*:*:*:*:*
0.0.2_pre15CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.0.2_pre15:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

5.0MEDIUM

AV:N/AC:L/Au:N/C:N/I:N/A:P

Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
2.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
2.52%
Probability of exploitation in next 30 days
EPSS Percentile
83.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0252 is in the 75th percentile among its peer group of 23,701 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

archives.seul.org / or/announce/Jan-2011/msg00000.html
Patch
blog.torproject.org / blog/tor-02129-released-security-patches
PatchVendor Advisory
exchange.xforce.ibmcloud.com / vulnerabilities/64888
gitweb.torproject.org / tor.git/blob/refs/heads/release-0.2.2:/ChangeLog
Patch
trac.torproject.org / projects/tor/ticket/2324
securityfocus.com / bid/45953