CVE-2021-29221Public exploit

Local privilege escalation via writable DLL search path

Published Apr 9, 2021 · Updated Aug 3, 2024

DLL search-order hijacking in Ericsson Erlang/OTP before 23.2.3 allows local users to execute code with another account's privileges. The Windows installer inherited permissive ACLs for a nondefault installation directory, letting users plant IPHLPAPI.dll beside erl.exe for loading. Exploitation requires a writable installation path and another user or a Local System erlsrv.exe service to start the Erlang emulator.

CVSS severity7.0
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DLL search-order hijacking in Ericsson Erlang/OTP before 23.2.3 allows local users to execute code with another account's privileges. The Windows installer inherited permissive ACLs for a nondefault installation directory, letting users plant IPHLPAPI.dll beside erl.exe for loading. Exploitation requires a writable installation path and another user or a Local System erlsrv.exe service to start the Erlang emulator.

The record

CVE
CVE-2021-29221
Published
Apr 9, 2021
Updated
Aug 3, 2024
Vendor
Ericsson
Product
Erlang/OTP
Classifications
CWE-426, T1574.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 23.2.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Ericsson · Erlang/OTPversion=< 23.2.3

Published CVSS scores

6.2NIST NVDAV:L/AC:H/Au:N/C:C/I:C/A:C
7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:N/UI:R/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-426Untrusted Search Path
T1574.001Hijack Execution Flow: DLL

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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