CVE-2021-33535Network attack vector

Authenticated code execution via time-server format string

Published Jun 25, 2021 · Updated Sep 17, 2024

Format-string injection in Weidmüller Industrial WLAN firmware allows remote authenticated users to execute code via a crafted time-server entry. The iw_console conio_writestr function treats the attacker-controlled time-server value as a format string, overflowing its time-server buffer. Low-privilege device credentials and network access to the console are required; successful exploitation runs attacker-supplied code on the appliance.

CVSS severity8.8
High
EPSS probability1.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format-string injection in Weidmüller Industrial WLAN firmware allows remote authenticated users to execute code via a crafted time-server entry. The iw_console conio_writestr function treats the attacker-controlled time-server value as a format string, overflowing its time-server buffer. Low-privilege device credentials and network access to the console are required; successful exploitation runs attacker-supplied code on the appliance.

The record

CVE
CVE-2021-33535
Published
Jun 25, 2021
Updated
Sep 17, 2024
Vendor
Weidmüller
Product
IE-WL(T)-BL-AP-CL
Classifications
CWE-134, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=IE-WL-BL-AP-CL-EU (2536600000) <=V1.16.18 (Build 18081617)
  2. Affected versionversion=IE-WL-BL-AP-CL-US (2536660000) <=V1.16.18 (Build 18081617)
  3. Affected versionversion=IE-WLT-BL-AP-CL-EU (2536650000) <=V1.16.18 (Build 18081617)
  4. Affected versionversion=IE-WLT-BL-AP-CL-US (2536670000) <=V1.16.18 (Build 18081617)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Weidmüller · IE-WL(T)-BL-AP-CLversion=IE-WL-BL-AP-CL-EU (2536600000) <=V1.16.18 (Build 18081617); version=IE-WL-BL-AP-CL-US (2536660000) <=V1.16.18 (Build 18081617); version=IE-WLT-BL-AP-CL-EU (2536650000) <=V1.16.18 (Build 18081617); version=IE-WLT-BL-AP-CL-US (2536670000) <=V1.16.18 (Build 18081617)
Weidmüller · IE-WL(T)-VL-AP-BR-CLversion=IE-WLT-VL-AP-BR-CL-EU (2536690000) <=V1.11.10 (Build 18122616); version=IE-WLT-VL-AP-BR-CL-US (2536710000) <=V1.11.10 (Build 18122616); version=IE-WL-VL-AP-BR-CL-EU (2536680000) <=V1.11.10 (Build 18122616); version=IE-WL-VL-AP-BR-CL-US (2536700000) <=V1.11.10 (Build 18122616)

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8CERT@VDECVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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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