Security readout for executives and security teams
Plain-English summary
An administrator-level attacker who can change OPNsense NTP settings could overwrite arbitrary system files with root privileges. This may disrupt firewall operations, alter security-sensitive files, or enable broader compromise. The attacker must already have access to the NTP configuration, which limits exposure but does not reduce the potentially severe impact.
Executive priority
Treat this as an urgent privileged-administration risk. Prioritize upgrading vulnerable firewalls, especially those with remotely accessible management interfaces or broad administrator access. Because exploitation requires NTP configuration privileges, immediately tightening administrative access can reduce exposure while upgrades are scheduled.
Technical view
The NTP configuration module insufficiently restricts GPS or PPS serial-port paths. Crafted path values can escape the intended directory and direct user-controlled data to arbitrary filesystem locations as root. The issue is classified as CWE-22 and CWE-73, with CVSS 3.1 score 9.0 and vector AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:H.
Likely exposure
Exposure is limited to vulnerable OPNsense installations where an attacker can access NTP configuration. Systems before opnsense/core 26.1.9 or BE/opnsense/core 26.4_20 are affected. Internet exposure of the management interface, weak administrator controls, or compromised privileged accounts would increase practical risk. The sources do not identify affected default configurations.
Exploitation context
No active exploitation is established by the supplied sources, and the CVE is not listed as KEV in the bundle. Exploitation requires high privileges but is remotely reachable according to the CVSS vector. Successful abuse can cross the NTP module’s intended security boundary and cause root-level arbitrary file writes.
Researcher notes
The supplied evidence supports path traversal through GPS or PPS serial-port parameters and root-context arbitrary file overwrite. It does not provide evidence of public exploitation, affected defaults, indicators of compromise, or a workaround beyond upgrading. Assessments should distinguish exploit preconditions from impact: privileges are high, while filesystem consequences are potentially system-wide.
Mitigation direction
- Upgrade opnsense/core to version 26.1.9 or later.
- Upgrade BE/opnsense/core to version 26.4_20 or later.
- Restrict OPNsense administrative and NTP configuration access to trusted personnel and management networks.
- Review vendor guidance for any additional branch-specific remediation or interim controls.
Validation and detection
- Confirm the installed OPNsense edition and exact core package version.
- Verify Community Edition systems run opnsense/core 26.1.9 or later.
- Verify Business Edition systems run BE/opnsense/core 26.4_20 or later.
- Review NTP GPS and PPS serial-port settings for unexpected paths or unauthorized changes.
- Review administrative audit records for suspicious NTP configuration activity, where available.
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-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupCWE-73: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-53581 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 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A: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
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:H/UI:N/S:C/C:H/I:L/A:H2.36GitHub_MVulnerability scoring details
Base CVSS 3.1 score
9CriticalVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/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
- https://github.com/opnsense/core/security/advisories/GHSA-872g-g543-j37mCVE reference, GitHub_M · x_refsource_CONFIRM
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 Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
External Control of File Name or Path
External Control of File Name or Path represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.