CVE-2020-10828Public exploitNetwork attack vector

Unauthenticated code execution via Authorization header overflow

Published Mar 26, 2020 · Updated May 5, 2025

Stack-based buffer overflow in cvmd on DrayTek Vigor3900, Vigor2960, and Vigor300B before 1.5.1 allows remote attackers to execute code. The cvmd HTTP server copies an attacker-controlled Authorization Digest value into a 100-byte stack buffer with memcpy using the input length. An unauthenticated request to /ACSServer/services/ACSServlet reaches the parser, allowing control-flow hijacking and command execution on the router.

CVSS severity9.8
Critical
EPSS probability20.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in cvmd on DrayTek Vigor3900, Vigor2960, and Vigor300B before 1.5.1 allows remote attackers to execute code. The cvmd HTTP server copies an attacker-controlled Authorization Digest value into a 100-byte stack buffer with memcpy using the input length. An unauthenticated request to /ACSServer/services/ACSServlet reaches the parser, allowing control-flow hijacking and command execution on the router.

The record

CVE
CVE-2020-10828
Published
Mar 26, 2020
Updated
May 5, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 26, 2020CVE publishedPublication date reported by the CVE source.
  2. May 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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