Zyxel VMG4005-B50B up to 5.13(ABRL.5.4)C0 DeletePortMapping buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.5$5k-$25k0.00

Summaryinfo

A vulnerability described as critical has been identified in Zyxel VMG4005-B50B up to 5.13(ABRL.5.4)C0. The impacted element is the function DeletePortMapping. Executing a manipulation can lead to buffer overflow. This vulnerability is tracked as CVE-2026-3871. The attack is only possible within the local network. No exploit exists.

Detailsinfo

A vulnerability was found in Zyxel VMG4005-B50B up to 5.13(ABRL.5.4)C0. It has been declared as critical. This vulnerability affects the function DeletePortMapping. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect availability. CVE summarizes:

A buffer overflow vulnerability in the UPnP DeletePortMapping() command in Zyxel VMG4005-B50B firmware versions through 5.13(ABRL.5.4)C0 could allow an adjacent attacker to trigger a temporary denial-of-service (DoS) condition affecting the UPnP function of the affected device.

The advisory is shared for download at zyxel.com. This vulnerability was named CVE-2026-3871 since 03/10/2026. The exploitation appears to be easy. Access to the local network is required for this attack. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 06/02/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.5

VulDB Base Score: 6.5
VulDB Temp Score: 6.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (Zyxel): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/10/2026 CVE reserved
06/02/2026 +83 days Advisory disclosed
06/02/2026 +0 days VulDB entry created
06/02/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: zyxel.com

Advisory: zyxel.com
Status: Confirmed

CVE: CVE-2026-3871 (🔒)
GCVE (CVE): GCVE-0-2026-3871
GCVE (VulDB): GCVE-100-367792

Entryinfo

Created: 06/02/2026 08:09
Changes: 06/02/2026 08:09 (62)
Complete: 🔍
Cache ID: 216::103

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