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Fencer Vulns
high 7.5

CVE-2021-38385 json

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 verificati…

published 2021-08-30 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-24837

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

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.

Patch / fix

  • torproject tor 0.3.5.16, 0.4.5.10, 0.4.6.7
  • tor Debian 14, Debian 13, Debian 12 0.4.5.10-1

debian advisories DEBIAN-CVE-2021-38385

  • tor Ubuntu Pro 16.04 LTS 0.2.9.14-1ubuntu1~16.04.3+esm1
  • tor Ubuntu Pro 18.04 LTS 0.3.2.10-1ubuntu0.2~esm2
  • tor Ubuntu Pro 20.04 LTS 0.4.2.7-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-38385

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tor openSUSE Tumbleweed 0.4.6.7-2.2
  • tor Package Hub 15 SP3, openSUSE Leap 15.3 0.4.6.7-bp153.2.6.1
  • tor Package Hub 15 SP2 0.4.6.7-bp152.2.15.1
  • tor openSUSE Leap 15.2 0.4.6.7-lp152.2.15.1

opensuse advisories openSUSE-SU-2024:11469-1openSUSE-SU-2021:1192-1openSUSE-SU-2021:1178-1openSUSE-SU-2021:1169-1

  • tor Alpine 3.14 0.4.5.10-r0
  • tor Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 0.4.6.7-r0

alpine advisories ALPINE-CVE-2021-38385

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • tor Arch Linux 0.4.6.7-1

arch linux advisories AVG-2302

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-38385 updated cvss 7.5

tor: assertion failure in signature verification

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.69% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.torproject.org https://bugs.torproject.org/tpo/core/tor/40078 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.