CVE-2011-0491
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not...
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
Exploit likelihood
What each source reports
NVD Score used
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
CVE-2011-0491- CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-20
- Updated
- 2026-11-02
CVE List No score
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
CVE-2011-0491- Updated
- 2026-11-02
EUVDEUVD-2011-0511 No score
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
EUVD-2011-0511- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gv9p-397w-xfq9 No score
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not...
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
GHSA-gv9p-397w-xfq9- Weakness
- CWE-20
- Updated
- 2026-11-02
OSV No score
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
CVE-2011-0491- Updated
- 2026-11-02
OSVDEBIAN-CVE-2011-0491 No score
The tor_realloc function in Tor before 0.2.1.29 and 0.2.2.x before 0.2.2.21-alpha does not validate a certain size value during memory allocation, which might allow remote attackers to cause a denial of service (daemon crash) via unspecified vectors, related to "underflow errors."
- Record
DEBIAN-CVE-2011-0491- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
torDebian:12 |
before 0.2.1.29-1 | 0.2.1.29-1 |
torDebian:13 |
before 0.2.1.29-1 | 0.2.1.29-1 |
torDebian:14 |
before 0.2.1.29-1 | 0.2.1.29-1 |
torDebian:5.0 |
before 0.2.1.29-1~lenny+1, plus listed versions 0.2.0.33-10.2.0.34-10.2.0.34-1~bpo40+10.2.0.35-10.2.0.35-1~lenny1 Show 45 moreShow less0.2.0.35-1~lenny20.2.1.10-alpha-10.2.1.11-alpha-10.2.1.12-alpha-10.2.1.13-alpha-10.2.1.14-rc-10.2.1.15-rc-10.2.1.16-rc-10.2.1.17-rc-10.2.1.18-10.2.1.19-10.2.1.2-alpha-10.2.1.20-10.2.1.20-20.2.1.21-10.2.1.21-1~bpo50+10.2.1.22-10.2.1.22-1~bpo50+10.2.1.23-10.2.1.23-20.2.1.25-10.2.1.25-1~bpo50+10.2.1.25-20.2.1.25-30.2.1.26-10.2.1.26-1~bpo50+10.2.1.26-1~lenny+10.2.1.26-1~lenny+20.2.1.26-1~lenny+40.2.1.26-1~lennyvolatile10.2.1.26-1~lennyvolatile20.2.1.26-20.2.1.26-30.2.1.26-40.2.1.26-4~bpo50+10.2.1.26-50.2.1.26-60.2.1.26-6~bpo50+10.2.1.4-alpha-10.2.1.5-alpha-10.2.1.6-alpha-10.2.1.7-alpha-10.2.1.7-alpha-20.2.1.8-alpha-10.2.1.9-alpha-1 |
0.2.1.29-1~lenny+1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2011-0491 is a medium vulnerability (CVSS 5.0) in Tor, published January 17, 2011. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.52%, the 84th percentile. Fixed in tor 0.2.1.29-1.
References
archives.seul.org/or/announce/Jan-2011/msg00000.html
gitweb.torproject.org/tor.git/blob/refs/heads/release-0.2.2:/ChangeLog
trac.torproject.org/projects/tor/ticket/2324
blog.torproject.org/blog/tor-02129-released-security-patches
exchange.xforce.ibmcloud.com/vulnerabilities/64888
securityfocus.com/bid/45953
nvd.nist.gov/vuln/detail/CVE-2011-0491
github.com/advisories/GHSA-gv9p-397w-xfq9
security-tracker.debian.org/tracker/CVE-2011-0491