Security readout for executives and security teams
Plain-English summary
CVE-2026-23769 is a cross-site scripting issue in NAVER lucy-xss-filter. The filter could fail to sanitize malicious JavaScript because default superset rule files were misconfigured. Applications relying on this library to clean untrusted web content may expose users to script execution in their browsers.
Executive priority
Treat as a moderate-priority web application security fix. Prioritize internet-facing applications and services that accept user-generated content. There is no cited evidence of active exploitation, but the issue affects a defensive library intended to prevent XSS.
Technical view
The CVE describes CWE-79 in lucy-xss-filter before commit e5826c0. The root cause is improper sanitization from misconfigured default superset rule files. CVSS 3.1 is 6.5: network reachable, low complexity, no privileges or user interaction, with low confidentiality and integrity impact and no availability impact.
Likely exposure
Exposure is most likely in web applications using NAVER lucy-xss-filter for sanitizing user-controlled HTML or scriptable content, especially if running code before commit e5826c0 or equivalent unfixed releases. The sources do not identify packaged version numbers or downstream products.
Exploitation context
The issue can allow malicious JavaScript execution when affected sanitization rules process attacker-controlled input. The source bundle does not report public exploitation, and CISA KEV status is false. No exploit details are provided in the cited sources.
Researcher notes
Key uncertainty: the CVE description says versions before commit e5826c0 are affected, while the structured affected entry lists the commit hash itself. Rely on the NAVER advisory and pull request for authoritative fix interpretation. Avoid assuming affected package versions not named in the sources.
Mitigation direction
- Review NAVER’s advisory and GitHub pull request for the official fix details.
- Update lucy-xss-filter to include commit e5826c0 or a vendor-designated fixed release.
- Inventory applications that rely on lucy-xss-filter for untrusted HTML sanitization.
- Apply compensating input/output validation where immediate library update is not feasible.
Validation and detection
- Check dependency manifests and build artifacts for lucy-xss-filter usage.
- Confirm deployed code includes commit e5826c0 or later vendor guidance.
- Review sanitizer configuration for default superset rule file usage.
- Test application XSS controls with approved internal security test cases only.
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.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-23769 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
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
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 vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N3.92.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cve.naver.com/detail/cve-2026-23769.htmlCVE reference · vendor-advisory
- https://github.com/naver/lucy-xss-filter/pull/32CVE reference · mitigation
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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.