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CVE-2009-0939

25
FAUCET Score

CVE-2009-0939 describes a critical vulnerability in Tor versions prior to 0.2.0.34, where incomplete IPv4 addresses are incorrectly treated as valid, leading to an unknown but potentially severe impact. With a CVSS score of 10.0, this flaw presents a network-based attack vector with low complexity, allowing for complete compromise of confidentiality, integrity, and availability. Despite its critical severity, there is no evidence of active exploitation, public exploit code, or significant community discussion, and it is not listed in the CISA KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
<= 0.2.0.33CPE matchmatch criteria
cpe:2.3:a:tor:tor:*:*:*:*:*:*:*:*
0.2.0.1CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.2.0.1:alpha:*:*:*:*:*:*
0.2.0.2CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.2.0.2:alpha:*:*:*:*:*:*
0.2.0.3CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.2.0.3:alpha:*:*:*:*:*:*
0.2.0.4CPE matchmatch criteria
cpe:2.3:a:tor:tor:0.2.0.4:alpha:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

10.0HIGH

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

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

Exploit Intelligence

EPSS Score
2.05%
Probability of exploitation in next 30 days
EPSS Percentile
79.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0205 is in the 63rd percentile among its peer group of 51,553 CVEs.

Social Chatter

No social media mentions found for this CVE.

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

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2009-0939

tor: multiple security fixes in 0.2.0.34 (CVE-2009-0936, CVE-2009-0937, CVE-2009-0938, CVE-2009-0939)

References

archives.seul.org / or/announce/Feb-2009/msg00000.html
secunia.com / advisories/33880
Vendor Advisory
secunia.com / advisories/34583
security.gentoo.org / glsa/glsa-200904-11.xml
securityfocus.com / bid/33713