What’s Vulnerable › Vulnerabilities

CVE-2021-29221

• Severity: high (CVSS 7.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-04-09 · updated 2026-06-17
• Weakness: CWE-426

Description

A local privilege escalation vulnerability was discovered in Erlang/OTP prior to version 23.2.3. By adding files to an existing installation's directory, a local attacker could hijack accounts of other users running Erlang programs or possibly coerce a service running with "erlsrv.exe" to execute arbitrary code as Local System. This can occur only under specific conditions on Windows with unsafe filesystem permissions.

Affected products

• Erlang OTP: before 23.2.3 — fixed in 23.2.3

How to fix

Upgrade to a fixed version: Erlang OTP 23.2.3. Check the vendor advisory for mitigations.

References

• https://deepsurface.com/deepsurface-security-advisory-local-privilege-escalation-in-erlang-on-windows-cve-2021-29221/
• https://github.com/erlang/otp/releases/tag/OTP-23.2.3
• https://deepsurface.com/deepsurface-security-advisory-local-privilege-escalation-in-erlang-on-windows-cve-2021-29221/
• https://github.com/erlang/otp/releases/tag/OTP-23.2.3

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