Security readout for executives and security teams
Plain-English summary
CVE-2026-25857 affects Tenda G300-F routers. A flaw in the WAN diagnostics feature can let someone who can access the router management interface run operating-system commands on the device. This is serious for exposed or weakly controlled admin interfaces, but the provided sources do not show known active exploitation.
Executive priority
Treat this as a high-priority network edge risk where Tenda G300-F routers are in use. Prioritize sites with exposed management access or shared administrator credentials. If no vendor fix is available, reduce exposure immediately and plan replacement for unsupported devices.
Technical view
The issue is CWE-78 OS command injection in formSetWanDiag. Firmware 16.01.14.2 and prior are described as affected. The vulnerable code builds a shell command using curl and attacker-controlled input without adequate neutralization. CVSS 4.0 is 8.6 high, with network attack vector, low complexity, and high privileges required.
Likely exposure
Organizations using Tenda G300-F routers are potentially exposed if their management interface is reachable by untrusted users, remote administrators, or compromised internal accounts. Internet-exposed management would increase business risk. The source bundle does not confirm a vendor patch or fixed firmware version.
Exploitation context
Public references include a technical blog tagged as exploit and a VulnCheck advisory. However, the source bundle marks CISA KEV as false and provides no cited evidence of active exploitation in the wild. Exploitation requires access to the affected management interface and high privileges according to the CVSS vector.
Researcher notes
The affected-version data is inconsistent in the supplied record: the description names firmware 16.01.14.2 and prior, while the affected object lists version "0" with defaultStatus "unaffected." Use vendor or device firmware evidence to confirm scope. Do not assume active exploitation without new KEV or credible reporting.
Mitigation direction
- Identify any Tenda G300-F devices and their firmware versions.
- Check Tenda guidance for fixed firmware or replacement recommendations.
- Disable internet exposure of router management interfaces.
- Restrict management access to trusted admin networks or VPN only.
- Rotate router admin credentials where exposure is suspected.
- Consider replacing affected devices if no supported fix is available.
Validation and detection
- Inventory Tenda G300-F routers across branch and remote sites.
- Confirm whether firmware is 16.01.14.2 or earlier.
- Review firewall rules for exposed management interfaces.
- Check administrative access logs for unexpected management activity.
- Monitor vendor and advisory pages for updated remediation details.
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-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-25857 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
- High
- CVSS
- 8.6 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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.
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:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
8.6HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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://blog.evan.lat/blog/cve-2026-25857/CVE reference, VulnCheck · technical-description, exploit
- https://www.tendacn.com/material/show/736333682028613CVE reference, VulnCheck · product
- https://www.vulncheck.com/advisories/tenda-g300-f-command-injection-via-formsetwandiagCVE 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 Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.