Security readout for executives and security teams
Plain-English summary
CVE-2020-25739 is an XSS protection failure in the Ruby gon gem before 6.4.0. Applications relying on gon to safely embed data into pages could expose users to script execution if unsafe fields are included. The sources name the fix but provide no CVSS score or active exploitation evidence.
Executive priority
Treat this as a targeted web application hygiene issue, not an emergency without exposure evidence. Prioritize internet-facing Ruby apps using gon before 6.4.0, especially where user data appears in pages.
Technical view
gon before 6.4.0 relied on MultiJson escape_mode for XSS escaping, but MultiJson did not honor that parameter. The fix changes json_dumper.rb so gon performs XSS escaping by default instead of relying on MultiJson. Debian and Ubuntu published ruby-gon security updates.
Likely exposure
Exposure is most likely in Ruby applications using the gon gem before 6.4.0, especially where untrusted or user-controlled values are serialized into client-side page data.
Exploitation context
The provided sources do not report active exploitation, and CVE KEV status is false. Impact depends on whether attacker-controlled values can reach gon output and be interpreted by a browser as executable script.
Researcher notes
Evidence is limited to the CVE description, upstream commit, and Debian/Ubuntu advisories. No CVSS, CWE, exploit status, or detailed affected version matrix is provided beyond gon before 6.4.0.
Mitigation direction
- Upgrade the gon gem to version 6.4.0 or later.
- Apply Debian or Ubuntu ruby-gon security updates where package-managed.
- Review vendor or distribution guidance for backported fixed package versions.
- Prioritize pages that expose authenticated users or sensitive workflows.
Validation and detection
- Inventory Ruby applications for the gon gem dependency and version.
- Check package-managed systems for installed ruby-gon update status.
- Review templates using gon for untrusted data exposure.
- Confirm XSS escaping behavior after update in regression tests.
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-2020-25739 mapping review
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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://github.com/gazay/gon/commit/fe3c7b2191a992386dc9edd37de5447a4e809bc7CVE reference · x_refsource_CONFIRM
- [debian-lts-announce] 20200926 [SECURITY] [DLA 2380-1] ruby-gon security updateCVE reference · mailing-list, x_refsource_MLIST
- USN-4560-1CVE reference · vendor-advisory, x_refsource_UBUNTU
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.