Security readout for executives and security teams
Plain-English summary
This is an older Tor vulnerability where certain pre-fix Tor versions could fail an internal assertion after mishandling signature verification behavior. In practical business terms, the public summary points to a remotely triggerable crash condition, so the main concern is service availability for organizations still running outdated Tor packages.
Executive priority
Prioritize remediation for any environment that relies on Tor availability or runs public-facing Tor infrastructure. For fully patched systems, this is a tracking item rather than an emergency because the bundle provides no active exploitation evidence.
Technical view
CVE-2021-38385, also TROVE-2021-007, affects Tor before 0.3.5.16, 0.4.5.10, and 0.4.6.7. The issue involves inconsistent handling between batch-signature verification and single-signature verification, leading to a remote assertion failure. The source bundle does not provide CVSS, CWE, detailed CPEs, or exploit mechanics.
Likely exposure
Exposure is most likely limited to systems running Tor older than 0.3.5.16, 0.4.5.10, or 0.4.6.7. Gentoo systems may have been addressed through GLSA-202305-11. The bundle does not identify other affected distributions or products.
Exploitation context
The source bundle says the failure is remote, but it does not cite active exploitation, public weaponization, or CISA KEV listing. Treat exploitation status as unconfirmed, not active.
Researcher notes
The public bundle is sparse: no CVSS, CWE, CPEs, or detailed patch notes are included. The key technical signal is a remote assertion failure caused by signature verification handling. Review the Tor bug and Tor Project advisory for exact code-path context before deeper validation.
Mitigation direction
- Inventory all Tor installations and record exact versions.
- Upgrade Tor to 0.3.5.16, 0.4.5.10, 0.4.6.7, or later.
- Apply vendor security updates, including Gentoo GLSA-202305-11 where relevant.
- Check Tor Project guidance for any deployment-specific instructions.
- Retire unsupported Tor branches where operationally possible.
Validation and detection
- Confirm installed Tor versions are at or above fixed releases.
- Review package manager history for applied Tor security updates.
- Check exposed Tor services for outdated binaries or containers.
- Review logs for unexplained Tor assertion failures or crashes.
- Verify Gentoo systems have applied GLSA-202305-11 where applicable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-38385 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://blog.torproject.org/CVE reference
- https://blog.torproject.org/node/2062CVE reference
- https://bugs.torproject.org/tpo/core/tor/40078CVE reference
- GLSA-202305-11CVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.