How severe is CVE-2017-0377?

CVE-2017-0377 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2017-0377 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-0377?

CVE-2017-0377 primarily affects Torproject Tor. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-0377?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-0377 published?

CVE-2017-0377 was published on 2017-07-02 and last updated on 2026-06-17.

CVE-2017-0377

CVE-2017-0377 is a high-severity vulnerability in Torproject Tor with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Torproject Tor
Published: 2017-07-02
Last modified: 2026-06-17

Description

Tor 0.3.x before 0.3.0.9 has a guard-selection algorithm that only considers the exit relay (not the exit relay's family), which might allow remote attackers to defeat intended anonymity properties by leveraging the existence of large families.

Frequently asked questions

What is CVE-2017-0377?: Tor 0.3.x before 0.3.0.9 has a guard-selection algorithm that only considers the exit relay (not the exit relay's family), which might allow remote attackers to defeat intended anonymity properties by leveraging the existence of large families.
How severe is CVE-2017-0377?: CVE-2017-0377 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2017-0377 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-0377?: CVE-2017-0377 primarily affects Torproject Tor. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-0377?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-0377 published?: CVE-2017-0377 was published on 2017-07-02 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:a:torproject:tor:0.3.0.1:alpha:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.2:alpha:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.3:alpha:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.4:*:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.5:*:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.6:*:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.7:*:*:*:*:*:*:*
cpe:2.3:a:torproject:tor:0.3.0.8:*:*:*:*:*:*:*

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