Security readout for executives and security teams
Plain-English summary
Fossil clients in the named version ranges may accept a TLS certificate without correctly checking the hostname. That weakens trust in secure connections and can let an intercepted connection appear valid. The sources identify fixed version thresholds but provide no CVSS score.
Executive priority
Treat this as a targeted maintenance priority for teams using Fossil over TLS. It is not listed as exploited, but it weakens a core trust control and should be corrected during normal security patch cycles.
Technical view
CVE-2021-36377 affects Fossil before 2.14.2 and 2.15.x before 2.15.2. The issue is improper TLS certificate hostname validation, where the hostname check is often skipped. This can undermine server identity verification during HTTPS/TLS use.
Likely exposure
Exposure is likely limited to environments using affected Fossil versions for remote repository access or other TLS-backed operations. The bundle does not identify affected CPEs, platforms beyond Fedora packaging, or specific deployment patterns.
Exploitation context
The source bundle does not report active exploitation, and KEV is false. Practical risk depends on whether an attacker can influence or intercept network traffic and present a certificate that passes other validation checks.
Researcher notes
The public bundle is sparse: no CVSS, CWE, CPE, exploit report, or detailed root-cause text is provided. Analysis should stay bounded to hostname validation behavior and the published fixed version thresholds.
Mitigation direction
- Upgrade Fossil to 2.14.2, 2.15.2, or a later fixed release.
- Apply relevant operating-system package updates, including Fedora advisory guidance where applicable.
- Inventory developer workstations, build images, and servers for installed Fossil versions.
- Check Fossil vendor guidance for any additional version-specific remediation details.
Validation and detection
- Confirm installed Fossil versions are not below 2.14.2 or in vulnerable 2.15.x builds.
- Review package manager records for Fossil update status across managed systems.
- Check CI containers and developer images for bundled Fossil binaries.
- Validate TLS hostname mismatch rejection in a controlled defensive test environment.
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-2021-36377 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://fossil-scm.org/forum/forumpost/8d367e16f53d93c789d70bd3bf2c9587227bbd5c6a7b8e512cccd79007536036CVE reference · x_refsource_MISC
- FEDORA-2021-8523af7a88CVE reference · vendor-advisory, x_refsource_FEDORA
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.