Vigor3910 FirmwareOperating system · Draytek

CVE-2022-32548

CRITICAL · 9.8 CVSS v3.1 Published 2022-08-29
Fix available
A fix is available. Upgrade to 4.3.1.1 / 4.4.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered on certain DrayTek Vigor routers before July 2022 such as the Vigor3910 before 4.3.1.1. /cgi-bin/wlogin.cgi has a buffer overflow via the username or password to the aa or ab field.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-120

A fixed-size buffer is filled without checking the length of the incoming data, so it overflows into neighbouring memory. This is the classic overflow attackers use to overwrite return addresses and hijack execution. The fix is strict length checks and safe, bounded string and memory functions.

General guidance for the classic buffer overflow class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Vigor3910 FirmwareOperating system
Affected:< 4.3.1.1
Vigor1000b FirmwareOperating system
Affected:< 4.3.1.1
Vigor2962 FirmwareOperating system
Affected:< 4.3.1.1
Vigor2962p FirmwareOperating system
Affected:< 4.3.1.1
Vigor2927 FirmwareOperating system
Affected:< 4.4.0
Vigor2927ax FirmwareOperating system
Affected:< 4.4.0
Vigor2927ac FirmwareOperating system
Affected:< 4.4.0
Vigor2927vac FirmwareOperating system
Affected:< 4.4.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.3.1.1 / 4.4.0 or later
Fixed in 4.3.1.14.4.0
Recommended fix High confidence

Vigor3910/Vigor1000b/Vigor2962/Vigor2962p: firmware 4.3.1.1 or later; Vigor2927 series: firmware 4.4.0 or later

  1. 1. Identify the exact DrayTek Vigor router model from the affected list (Vigor3910, Vigor1000b, Vigor2962, Vigor2962p, Vigor2927, Vigor2927ax, Vigor2927ac, or Vigor2927vac)
  2. 2. Access the router's web administration interface or console
  3. 3. Navigate to the firmware update or system maintenance section
  4. 4. Download the appropriate firmware version from the official DrayTek support website: For Vigor3910, Vigor1000b, Vigor2962, Vigor2962p - use version 4.3.1.1 or later; For Vigor2927 series - use version 4.4.0 or later
  5. 5. Upload the firmware file to the router and initiate the update process
  6. 6. Wait for the update to complete and the router to reboot
  7. 7. Verify the firmware version has been updated successfully
  8. 8. After upgrade, ensure the /cgi-bin/wlogin.cgi endpoint is no longer exposed to untrusted networks if possible
Caveat Firmware updates carry a risk of device failure if interrupted; ensure stable power during upgrade

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,550. Get the upgrade done

Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-32548 in production — separate from our analysis above.

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