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CVE-2011-2768· NVD / CVE Program· CNA mitre

Tor before 0.2.2.34, when configured as a client or bridge, sends a TLS certificate chain as part of an outgoing OR connection, which allows

Tor before 0.2.2.34, when configured as a client or bridge, sends a TLS certificate chain as part of an outgoing OR connection, which allows remote relays to bypass intended anonymity properties by reading this chain and then determining the set of entry guards that the client or bridge had selected.

MediumCVSS 5.8 · v2.0—No exploit Fix available
Published
Dec 22, 2011
Updated
Jun 16, 2026
EPSS
0.7% · 52th percentile
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Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

Affected systems

VendorProduct
tortor

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • tor torup to 0.2.2.33 inclusive
  • tor tor0.0.2
  • tor tor0.0.3
  • tor tor0.0.4
  • tor tor0.0.5
  • tor tor0.0.6
  • tor tor0.0.6.1
  • tor tor0.0.6.2
  • tor tor0.0.7
  • tor tor0.0.7.1
  • tor tor0.0.7.2
  • tor tor0.0.7.3
  • tor tor0.0.8
  • tor tor0.0.8.1
  • tor tor0.0.9
  • tor tor0.0.9.1
  • tor tor0.0.9.10
  • tor tor0.0.9.2
  • tor tor0.0.9.3
  • tor tor0.0.9.4

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12torbefore 0.2.2.34-10.2.2.34-1
Debian:5.0torbefore 0.2.1.31-1~lenny+10.2.1.31-1~lenny+1
Debian:6.0torbefore 0.2.1.31-10.2.1.31-1
openSUSE:Tumbleweedtorbefore 0.2.8.11-1.10.2.8.11-1.1

Same product

tor: all records

Other highest-scoring records for the same primary product.

  • CVE-2010-1676Heap-based buffer overflow in Tor before 0.2.1.28 and 0.2.2.x before 0.2.2.20-alpha allows remote attackers to cause a denial of service (da
    42Plan
  • CVE-2009-0939Tor before 0.2.0.34 treats incomplete IPv4 addresses as valid, which has unknown impact and attack vectors related to "Spec conformance," as
    41Plan
  • CVE-2009-0414Unspecified vulnerability in Tor before 0.2.0.33 has unspecified impact and remote attack vectors that trigger heap corruption.
    41Plan
  • CVE-2008-5398Tor before 0.2.0.32 does not properly process the ClientDNSRejectInternalAddresses configuration option in situations where an exit relay is
    38Monitor
  • CVE-2011-2778Multiple heap-based buffer overflows in Tor before 0.2.2.35 allow remote attackers to cause a denial of service (memory corruption) or possi
    31Monitor
  • CVE-2006-3409Integer overflow in Tor before 0.1.1.20 allows remote attackers to execute arbitrary code via crafted large inputs, which result in a buffer
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:tor0.2.2.34-1 · Debian:12Package registry (OSV)
opensuse:tor0.2.8.11-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

    If successful

    Confidentiality
    P · data can be read
    Integrity
    P · data or configuration can be modified
    Availability
    none
    Attack complexity
    M
    Confidentiality impact
    P
    Integrity impact
    P
    Availability impact
    None

    Weakness class (CWE)

    CWE-264 · Permissions, Privileges, and Access Controls

    CVSS vector

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

    nvd-primary

    Attack context

    MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

    MITRE has no CAPEC/ATT&CK mapping for this CWE.

    Noroxi analysis

    No Noroxi analysis for this record yet

    We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

    We use this product, ask for help

    Change log

    1. Fix✗ → ✓

    For records you follow, these changes also arrive as notifications. →

    References

    Vendor advisories and official records. Exploit/PoC links are deliberately left out.

    All records