Security readout for executives and security teams
Plain-English summary
This is a critical remote code execution flaw in DrayTek Vigor3900, Vigor2960, and Vigor300B devices before 1.5.1. An unauthenticated attacker could send a remote HTTP request and potentially take control of the device. Treat internet-reachable affected devices as urgent network-edge risk.
Executive priority
Prioritize within emergency patch and exposure-reduction work for internet-facing network infrastructure. Remote unauthenticated code execution on edge devices can enable full device compromise, traffic interception, or pivoting. Urgency is highest for externally reachable or unmanaged DrayTek appliances.
Technical view
CVE-2020-10823 is a stack-based buffer overflow, CWE-787, in the var parameter of /cgi-bin/activate.cgi. CVSS 3.1 is 9.8 with network attack vector, low complexity, no privileges, and no user interaction. The source describes remote HTTP-triggered code execution on affected DrayTek devices before 1.5.1.
Likely exposure
Exposure is likely where affected DrayTek Vigor3900, Vigor2960, or Vigor300B appliances are reachable over HTTP, especially from untrusted networks. The provided data does not identify affected CPEs or deployment prevalence, so asset inventory is necessary.
Exploitation context
The provided bundle says this CVE is not in CISA KEV. Public references include a vulnerability write-up and vendor advisory, but the bundle does not provide evidence of active exploitation. The flaw is remotely reachable and requires no authentication or user interaction, increasing risk.
Researcher notes
Evidence supports remote code execution through a stack buffer overflow in /cgi-bin/activate.cgi via the var parameter. The bundle identifies issue 1 of 3, affected models, and pre-1.5.1 versions. It does not provide CPE data, live exploitation evidence, or detailed vendor mitigation beyond version boundary.
Mitigation direction
- Identify DrayTek Vigor3900, Vigor2960, and Vigor300B devices in inventory.
- Upgrade affected devices to firmware 1.5.1 or later per vendor guidance.
- Restrict management HTTP access to trusted administrative networks.
- Check the DrayTek advisory for current remediation details.
- Review exposed edge devices for suspicious administrative access.
Validation and detection
- Confirm device model and firmware version on each DrayTek appliance.
- Verify affected devices are not running firmware before 1.5.1.
- Check whether /cgi-bin/activate.cgi is reachable from untrusted networks.
- Review firewall rules limiting management access.
- Document remediation status for each affected appliance.
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-787: 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 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-2020-10823 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
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
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:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://slashd.ga/2020/03/draytek-vulnerabilities/CVE reference · x_refsource_MISC
- https://www.draytek.com/about/security-advisory/vigor3900-/-vigor2960-/-vigor300b-stack-based-buffer-overflow-vulnerability/CVE reference · 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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.