CVE-2021-36770
HIGHDescription
Encode.pm, as distributed in Perl through 5.34.0, allows local users to gain privileges via a Trojan horse Encode::ConfigLocal library (in the current working directory) that preempts dynamic module loading. Exploitation requires an unusual configuration, and certain 2021 versions of Encode.pm (3.05 through 3.11). This issue occurs because the || operator evaluates @INC in a scalar context, and thus @INC has only an integer value.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 70% of all known CVEs.
References
Related Vulnerabilities
Other CWE-427 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-27955 | Critical | 9.8 | 83% | - | - |
| CVE-2017-6517 | Critical | 9.8 | 46% | - | - |
| CVE-2020-3153 | Medium | 6.5 | 27% | KEV + Ransom | Fix |
| CVE-2024-48990 | High | 7.8 | 20% | - | Fix |
| CVE-2019-9491 | High | 7.8 | 13% | - | - |
| CVE-2020-3433 | High | 7.8 | 10% | KEV + Ransom | Fix |
Common questions
How do I fix CVE-2021-36770?
Upgrade libencode-perl on debian 11 to 3.08-1+deb11u1 or later.
Is CVE-2021-36770 being actively exploited?
Not that we know of. CVE-2021-36770 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.4% is the estimated probability that it will be exploited in the next 30 days. That is higher than 70% of all scored CVEs.
How severe is CVE-2021-36770?
CVE-2021-36770 has a CVSS v3 base score of 7.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-36770 affect?
Published advisories record a fix for libencode-perl (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.