Security readout for executives and security teams
Plain-English summary
A device on the same network can plant malicious web content into OpenWrt LuCI’s DHCPv6 lease display. If an administrator later views that lease page, the content can run in the administrator’s browser. That creates risk to router administration sessions and managed network infrastructure.
Executive priority
Treat this as urgent for OpenWrt-managed environments with shared, guest, or semi-trusted networks. The business risk is administrative session compromise through routine router management activity, but remediation details are incomplete in the provided sources.
Technical view
LuCI fails to properly encode DHCPv6 lease hostnames before rendering status tables, creating stored cross-site scripting. The reported path involves a DHCPv6 Client FQDN value and requires administrator interaction by viewing the lease page. CVSS v4.0 is 9.4, with adjacent attack vector, no privileges, and user interaction present.
Likely exposure
Exposure is most likely on OpenWrt systems using LuCI where DHCPv6 clients can join an adjacent network and administrators use LuCI lease status pages. The provided bundle does not identify fixed versions, exact affected version ranges, or CPEs.
Exploitation context
The source bundle does not cite active exploitation, and KEV is false. Exploitation requires adjacency to the target network and an administrator viewing the affected LuCI DHCP lease interface. No public exploit status beyond the advisories is provided here.
Researcher notes
Evidence supports stored XSS in LuCI DHCPv6 lease hostname rendering, mapped to CWE-79. The bundle lacks affected version ranges, patch commits, fixed releases, and independent exploitation confirmation. Avoid assuming broader OpenWrt components are affected beyond LuCI as stated.
Mitigation direction
- Check the OpenWrt LuCI advisory for fixed versions and upgrade guidance.
- Restrict LuCI administration access to trusted management networks only.
- Segment untrusted DHCPv6 clients away from router administration paths.
- Limit administrative browsing of DHCP lease pages until vendor guidance is applied.
- Monitor OpenWrt and LuCI advisories for updated affected-version details.
Validation and detection
- Inventory OpenWrt devices running LuCI and DHCPv6 services.
- Compare installed LuCI packages against the vendor advisory when version details are available.
- Confirm LuCI is not reachable from untrusted or guest networks.
- Review whether administrators regularly inspect DHCPv6 lease status pages.
- Track CVE and advisory updates for fixed package identifiers.
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-2026-61876 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
- Critical
- CVSS
- 9.4 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H——VulnCheckCVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H2.16VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.4CriticalVector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- GitHub Security Advisory (GHSA-686p-p8p9-x6fh)CVE reference, VulnCheck · vendor-advisory
- VulnCheck Advisory: LuCI DHCPv6 Lease Hostname Stored Cross-Site ScriptingCVE reference, VulnCheck · third-party-advisory
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.