Analyst readout for executives and security teams
Plain-English summary
CVE-2026-9389 is a critical buffer overflow in Tenda F456 firmware 1.0.0.5. A remote attacker with required authentication may be able to compromise the router’s confidentiality, integrity, and availability. Public exploit material is reported, but the provided sources do not confirm active exploitation or a vendor patch.
Executive priority
Prioritize identification and containment within router inventories. This is critical because compromise of an edge router can affect traffic control, availability, and downstream trust. Urgency is high, but evidence does not support claiming active exploitation from the supplied sources.
Technical view
The vulnerability affects frmL7ImForm in /goform/L7Im. Manipulation of the page argument can cause a buffer overflow, mapped to CWE-119 and CWE-120. The CVSS 2.0 vector is network-accessible, low complexity, authenticated, with complete confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Tenda F456 devices running firmware 1.0.0.5. Risk is highest where router administration is reachable from untrusted networks. The CVSS vector indicates authentication is required, so weak, shared, or compromised admin credentials increase practical exposure.
Exploitation context
The source bundle says exploit information has been publicly disclosed and may be used. CISA KEV is false, and no cited source confirms exploitation in the wild. Treat public proof-of-concept availability as a strong urgency signal, not evidence of active compromise.
Researcher notes
The record identifies the vulnerable function, endpoint, parameter, affected firmware, and CWE classes, but does not provide a confirmed fixed version, vendor advisory details, or validated IoCs. Avoid expanding scope beyond Tenda F456 1.0.0.5 unless later vendor or CVE updates support it.
Mitigation direction
- Inventory Tenda F456 devices and confirm firmware version 1.0.0.5.
- Restrict router administration to trusted management networks only.
- Remove any internet exposure of the management interface.
- Check Tenda guidance for firmware updates, advisories, or replacement direction.
- Review logs for suspicious access involving /goform/L7Im.
Validation and detection
- Confirm whether any deployed device is Tenda F456 firmware 1.0.0.5.
- Verify management access is blocked from untrusted networks.
- Check whether default or weak administrator credentials remain in use.
- Monitor administrative access logs for unexpected source addresses.
- Track vendor and CVE records for patch or mitigation updates.
Public sources used
Based on public source material and reviewed before publication.
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-119: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-120: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2026-9389 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 (2.0)
- Known Exploited
- No
- Published
Vector: AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
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
4 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.
AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR 8 10 VulDB CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R 2.8 5.9 VulDB CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R 2.8 5.9 VulDB CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P — — VulDB Vulnerability scoring details
Base CVSS 4.0 score
8.7 HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
Base CVSS 3.1 score
8.8 HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
Base CVSS 3.0 score
8.8 HighVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
Base CVSS 2.0 score
9 CriticalVector: AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timeline VulDB
Advisory disclosed
- Source timeline VulDB
VulDB entry created
- CVE reserved CVE Program
The CVE ID was reserved by the assigning CNA.
- Source timeline VulDB
VulDB entry last update
- CVE published CVE Program
The CVE record was published.
- CVE updated CVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 source CVE List V5
- VDB-365352 | Tenda F456 L7Im frmL7ImForm buffer overflow CVE reference, VulDB · vdb-entry, technical-description
- VDB-365352 | CTI Indicators (IOB, IOC, IOA) CVE reference, VulDB · signature, permissions-required
- Submit #813444 | tenda F456 v1.0.0.5 Stack-based Buffer Overflow CVE reference, VulDB · third-party-advisory
- https://github.com/Litengzheng/vuldb_new/blob/main/F456/vul_2/README.md CVE reference, VulDB · exploit
- https://www.tenda.com.cn/ CVE reference, VulDB · product
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 Restriction of Operations within the Bounds of a Memory Buffer
Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.