How severe is CVE-2021-38385?

CVE-2021-38385 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 none, integrity none, and availability high.

Is CVE-2021-38385 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38385?

CVE-2021-38385 affects Torproject Tor. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-38385?

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-2021-38385 published?

CVE-2021-38385 was published on 2021-08-30 and last updated on 2026-06-17.

CVE-2021-38385

CVE-2021-38385 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-617.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-617
Affected product: Torproject Tor
Published: 2021-08-30
Last modified: 2026-06-17

Description

Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7 mishandles the relationship between batch-signature verification and single-signature verification, leading to a remote assertion failure, aka TROVE-2021-007.

Frequently asked questions

What is CVE-2021-38385?: Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7 mishandles the relationship between batch-signature verification and single-signature verification, leading to a remote assertion failure, aka TROVE-2021-007.
How severe is CVE-2021-38385?: CVE-2021-38385 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 none, integrity none, and availability high.
Is CVE-2021-38385 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38385?: CVE-2021-38385 affects Torproject Tor. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-38385?: 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-2021-38385 published?: CVE-2021-38385 was published on 2021-08-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*

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