Security readout for executives and security teams
Plain-English summary
DD-WRT build 45723 has a memory-handling flaw in its UPnP discovery service. An unauthenticated attacker who can reach that service may crash the device or potentially run code on it, threatening network availability, configuration integrity, and traffic confidentiality.
Executive priority
Treat confirmed build 45723 deployments as urgent, especially on perimeter or broadly reachable devices. Prioritize exposure reduction and vendor-supported remediation. Public exploit information and potential full device compromise justify rapid action, although active exploitation is not established by the supplied evidence.
Technical view
Oversized UUID data in crafted M-SEARCH packets can trigger a CWE-120 buffer overflow in DD-WRT 45723. The CVSS 3.1 score is 9.8 because exploitation is network-accessible, low-complexity, requires no privileges or user interaction, and may compromise confidentiality, integrity, and availability.
Likely exposure
Confirmed scope is limited to DD-WRT version 45723. Devices are most concerning when their UPnP network discovery service is enabled and reachable from untrusted systems. The supplied evidence does not establish whether other builds are affected.
Exploitation context
ExploitDB and advisory references indicate public exploit information exists. However, CVE-2021-47854 is not listed as KEV in the supplied bundle, and no cited evidence establishes active exploitation in the wild. Treat exploit availability as elevated risk, not proof of compromise.
Researcher notes
The evidence identifies the vulnerable input as oversized UUID content in M-SEARCH traffic, but does not establish the vulnerable function, memory protections, reliable code-execution conditions, fixed version, or broader version range. Avoid extending affected-product claims beyond build 45723 without additional vendor evidence.
Mitigation direction
- Inventory DD-WRT devices and prioritize any running build 45723.
- Check current DD-WRT guidance for a fixed build and apply the vendor-approved update.
- Reduce untrusted network access to UPnP discovery while remediation is pending.
- Preserve configuration backups before firmware changes and verify device compatibility.
Validation and detection
- Confirm each device's installed DD-WRT build through trusted administrative records or its management interface.
- Determine whether UPnP discovery is enabled and reachable from untrusted network segments.
- After remediation, verify the reported build no longer equals 45723.
- Review device and network telemetry for abnormal discovery traffic, crashes, or unexpected configuration changes.
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-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 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-2021-47854 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.
SSVC decision data
CVSS vector scores
2 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
8.7HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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
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
- ExploitDB-49730CVE reference, VulnCheck · exploit
- DD-WRT Official Vendor HomepageCVE reference, VulnCheck · product
- DD-WRT Software Download RepositoryCVE reference, VulnCheck · product
- SSD Security Advisory for DD-WRT UPNP Buffer OverflowCVE reference, VulnCheck · technical-description
- VulnCheck Advisory: DD-WRT 45723 - UPNP Buffer OverflowCVE 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.
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.