Security readout for executives and security teams
Plain-English summary
CVE-2026-2736 is a reflected XSS issue in Alkacon OpenCms 18.0. A user who opens a crafted search URL could have attacker-controlled JavaScript run in their browser. Business impact is mainly account abuse or data exposure through the victim’s browser, especially for authenticated staff using the CMS.
Executive priority
Treat as a timely remediation item, not an emergency unless OpenCms 18.0 is internet-facing or used by privileged staff. Prioritize patch verification and user-awareness controls because exploitation depends on user interaction.
Technical view
OpenCms 18.0 reflects the ‘q’ parameter in ‘/search/index.html’ without sufficient neutralization, enabling CWE-79 reflected XSS. The CVSS 4.0 score is 5.1, with network access, low attack complexity, no privileges required, and user interaction required. Scope impacts are limited to confidentiality and integrity in the victim browser context.
Likely exposure
Organizations running Alkacon OpenCms 18.0 with the search page exposed are the stated affected population. The CVE record lists other versions as unaffected by default, but administrators should verify their deployed version and vendor guidance.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires convincing a victim to open a malicious URL. Risk increases where privileged CMS users access untrusted links while authenticated.
Researcher notes
Evidence is limited to the CVE record and INCIBE advisory reference. The bundle identifies OpenCms 18.0, endpoint ‘/search/index.html’, parameter ‘q’, CWE-79, CVSS 5.1, and no KEV status. No public exploit confirmation is provided in the supplied sources.
Mitigation direction
- Identify whether any OpenCms instance is version 18.0.
- Review the INCIBE and vendor advisory for the available patch or update path.
- Apply the vendor-provided patch or upgrade if applicable.
- Limit exposure of CMS administrative use from untrusted browsing contexts.
- Consider temporary filtering for suspicious search parameter input until patched.
Validation and detection
- Inventory OpenCms deployments and confirm exact version numbers.
- Check whether /search/index.html is reachable on affected sites.
- In staging, verify the q parameter is safely encoded in responses.
- Confirm patched systems no longer reflect unsafe script-like input.
- Review web logs for unusual search URLs targeting the q parameter.
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-2026-2736 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
- 5.1 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA: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:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
5.1MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-alkacons-opencmsCVE reference · patch
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.