Security readout for executives and security teams
Plain-English summary
CVE-2026-23768 affects NAVER lucy-xss-filter. When specific filtering options are enabled, crafted embed or object tags can cause the server to make HEAD requests to attacker-chosen URLs. This is an SSRF-style issue. Business impact is mainly unintended internal or external network probing and limited data exposure, not direct server takeover based on the provided sources.
Executive priority
Treat as a moderate-priority remediation for applications that process user-submitted HTML. Prioritize internet-facing systems and servers with access to internal services. There is no provided evidence of active exploitation, but SSRF behavior can create meaningful internal exposure if egress controls are weak.
Technical view
The issue is classified as CWE-918. lucy-xss-filter before commit 7c1de6d can issue server-side HEAD requests to arbitrary URLs when ObjectSecurityListener or EmbedSecurityListener is enabled and embed/object tags use a src attribute without a file extension. CVSS 3.1 is 6.1, network exploitable, low complexity, no privileges, user interaction required, changed scope, low confidentiality and integrity impact.
Likely exposure
Exposure is likely limited to applications using lucy-xss-filter with ObjectSecurityListener or EmbedSecurityListener enabled and processing user-controlled HTML containing embed or object tags. Applications not using those options, or not accepting such HTML, appear less exposed based on the advisory description.
Exploitation context
The source bundle does not indicate known active exploitation, and the CVE is not listed as KEV. Exploitation requires user interaction per CVSS and specific filter configuration. The observable effect is inducing server-side HEAD requests to arbitrary URLs, which may matter if the server can reach internal services.
Researcher notes
Key uncertainty: the affected-version metadata in the bundle lists the commit hash while the description says versions before commit 7c1de6d. Use the vendor advisory and pull request as authoritative. Avoid assuming broader products or exploit availability; the provided sources only support lucy-xss-filter and the described HEAD-request behavior.
Mitigation direction
- Review NAVER advisory and GitHub pull request 31 for the official fix details.
- Update lucy-xss-filter to a version including commit 7c1de6d, if applicable.
- Disable ObjectSecurityListener and EmbedSecurityListener if not required.
- Restrict server egress to internal metadata and administrative endpoints.
- Monitor outbound HEAD requests from affected application servers.
Validation and detection
- Inventory applications using NAVER lucy-xss-filter.
- Confirm deployed code is at or after commit 7c1de6d.
- Check whether ObjectSecurityListener or EmbedSecurityListener is enabled.
- Review whether users can submit embed or object HTML tags.
- Inspect logs for unusual outbound HEAD requests from application servers.
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-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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-2026-23768 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cve.naver.com/detail/cve-2026-23768.htmlCVE reference · vendor-advisory
- https://github.com/naver/lucy-xss-filter/pull/31CVE 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.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.