Security readout for executives and security teams
Plain-English summary
This is a critical router flaw in D-Link DIR-825 R1 devices. The web interface can be attacked remotely before login, potentially letting an attacker take control of the device. CISA lists this CVE in its Known Exploited Vulnerabilities catalog, so affected internet-exposed devices should be treated as urgent exposure.
Executive priority
Treat this as an urgent perimeter-device risk. A vulnerable router could give an attacker a foothold before authentication, and CISA KEV status means exploitation is not theoretical. Confirm whether these devices exist, then update, isolate, or retire them quickly.
Technical view
CVE-2020-29557 is a CWE-119 buffer overflow in the D-Link DIR-825 R1 web interface affecting devices through firmware 3.0.1 before 2020-11-20. The CVSS 3.1 score is 9.8, with network attack vector, no privileges, no user interaction, and full confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to D-Link DIR-825 R1 routers running firmware through 3.0.1 before 2020-11-20, especially where the web management interface is reachable from untrusted networks. The provided affected-product metadata is incomplete, so inventory confirmation is important.
Exploitation context
The source bundle says CISA KEV includes CVE-2020-29557, which supports known exploitation. Public references include a D-Link download page and an external research write-up. The bundle does not provide exploit prevalence, targeting patterns, or a definitive fixed firmware version.
Researcher notes
The evidence identifies pre-authentication RCE via a web-interface buffer overflow, but the prompt bundle does not include safe validation artifacts, affected CPEs, or exact fixed firmware details. Avoid assuming broader D-Link impact without source support.
Mitigation direction
- Inventory all D-Link DIR-825 R1 devices and record firmware versions.
- Check D-Link guidance/downloads for fixed firmware or replacement direction.
- Remove web management exposure from the internet and untrusted networks.
- Replace devices if vendor-supported remediation cannot be confirmed.
- Prioritize remediation for remote sites, branch networks, and unmanaged routers.
Validation and detection
- Confirm whether any DIR-825 R1 device runs firmware through 3.0.1 before 2020-11-20.
- Verify the management interface is not reachable from the public internet.
- Review firewall, VPN, and remote management rules for unintended access.
- Check CISA KEV tracking for required remediation timelines.
- Document evidence of firmware update, isolation, or device retirement.
Public sources used
Michael Williams reviewed this cited source version on .
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-119: Exact CWE lookup
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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-2020-29557 mapping review
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Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- 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.
CISA KEV status
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://www.dlink.ru/ru/download2/5/19/2354/441/CVE reference · x_refsource_MISC
- https://shaqed.github.io/dlink/CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29557CVE reference · government-resource
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.