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CVE Record

CVE-2026-77946: TRENDnet TEW-821DAP NTP Timezone Configuration apply_time.cgi uci_safe_get stack-based overflow

A vulnerability was determined in TRENDnet TEW-821DAP 2.2.01b05. Affected by this vulnerability is the function uci_safe_get of the file /cgi-bin/apply_time.cgi of the component NTP Timezone Configuration Handler. Executing a manipulation of the argument system.ntp.server/system.ntp.enable_server/cameo.time.time_zone/cameo.cameo.syslog_server can lead to stack-based buffer overflow. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized.

CriticalCVSS 10Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

TRENDnet TEW-821DAP firmware 2.2.01b05 contains a remotely reachable memory-corruption flaw in its time-configuration handler. An unauthenticated attacker who can reach the affected interface could potentially disrupt the device or compromise data and settings. The supplied CVSS 4.0 score is 10.0.

Executive priority

Treat exposed affected devices as an immediate remediation priority because exploitation requires no privileges or user interaction and could produce severe operational and security impact. Prioritize external-facing units first, then restrict management access while seeking official TRENDnet remediation.

Technical view

Crafted values supplied to several NTP, timezone, and syslog parameters handled by /cgi-bin/apply_time.cgi can trigger a stack-based buffer overflow in uci_safe_get. The supplied vector indicates network access, low complexity, no privileges, no user interaction, and high impacts across confidentiality, integrity, and availability.

Likely exposure

Exposure is established only for TEW-821DAP firmware 2.2.01b05. Risk is greatest where the administrative web interface is reachable from the internet or untrusted networks. The supplied evidence does not establish whether other firmware versions are affected or safe.

Exploitation context

A technical exploit description has been publicly disclosed, and the CVSS vector marks exploit maturity as proof-of-concept. However, the CVE is not listed as KEV in the supplied bundle, and no cited source establishes active exploitation in the wild.

Researcher notes

The reported parameters are system.ntp.server, system.ntp.enable_server, cameo.time.time_zone, and cameo.cameo.syslog_server. Classification includes CWE-119 and CWE-121. Evidence is primarily third-party and public disclosure material; the bundle provides no vendor advisory, fixed version, incident evidence, or confirmed exploitation outcome.

Mitigation direction

  • Identify and isolate TEW-821DAP units running firmware 2.2.01b05.
  • Block internet and untrusted-network access to the administrative web interface.
  • Check TRENDnet guidance for fixed firmware or official mitigation; the supplied sources name none.
  • Consider replacing exposed units if no supported remediation becomes available.

Validation and detection

  • Confirm each device model and installed firmware using trusted inventory or local administration.
  • Verify the management interface is inaccessible from internet and untrusted user networks.
  • Review available logs for unexpected apply_time.cgi requests or time-configuration changes.
  • Do not validate production devices using the publicly disclosed exploit.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

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 lookup
cwe · low confidence lookup

CWE-121: 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 lookup
cve · low confidence lookup

CVE-2026-77946 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
10 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Official CVE source material

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.

4CVSS vectors
6Timeline events
1ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: yesTechnical Impact: total

CVSS vector scores

4 official scores

We 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.

ScoreVersionSeverityVectorExploitImpactSource
10CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P——VulDB
10CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.96VulDB
10CVSS 3.0CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.96VulDB
10CVSS 2.0CriticalAV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:UR1010VulDB

Vulnerability scoring details

Base CVSS 4.0 score

10Critical
CVSS 4.0 vector shape for CVE-2026-77946Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineVulDB

    Advisory disclosed

  2. Source timelineVulDB

    VulDB entry created

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. Source timelineVulDB

    VulDB entry last update

  5. CVE publishedCVE Program

    The CVE record was published.

  6. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
TRENDnetTEW-821DAP2.2.01b05Listed
Weakness

CWE details

CWE-119CWE-121

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.