CVE-2021-38385

Exp

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.

Published: 2021-08-30 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-38385 is rated High Exploit Risk (71/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.69%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-38385

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-38385

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 1.63% 1.69% +0.05%
2 2026-06-15 0.60% 1.63% +1.04%
3 2026-05-06 — 0.60% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38385

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-38385

OS Trackers for CVE-2021-38385

vendor priority summary link
alpine high CVE-2021-38385: 1 source package rows (tor); 19 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 12. https://security.alpinelinux.org/vuln/CVE-2021-38385
debian not yet assigned CVE-2021-38385 not yet assigned priority: Debian including 1 source packages (tor), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38385
gentoo normal CVE-2021-38385: 1 GLSA(s) (202305-11), 1 atom(s) (net-vpn/tor); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-38385
ubuntu medium CVE-2021-38385 medium priority: Ubuntu including 1 source packages (tor), 14 status rows across 14 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 8, released 4, ignored 2. https://ubuntu.com/security/CVE-2021-38385

Affected software / configurations for CVE-2021-38385

Vendor Product Version Raw CPE
torproject tor < 0.3.5.16 cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
torproject tor >= 0.4.0.0, < 0.4.5.10 cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*
torproject tor >= 0.4.6.0, < 0.4.6.7 cpe:2.3:a:torproject:tor:*:*:*:*:*:*:*:*

References for CVE-2021-38385

URL Tags
https://blog.torproject.org Release Notes Vendor Advisory
https://blog.torproject.org/node/2062 Release Notes Vendor Advisory
https://bugs.torproject.org/tpo/core/tor/40078 Exploit Issue Tracking Vendor Advisory
https://security.gentoo.org/glsa/202305-11
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