CVE-2020-36846
CRITICAL
Published May 30, 2025
Modified Apr 15, 2026
Description
A buffer overflow, as described in CVE-2020-8927, exists in the embedded Brotli library. Versions of IO::Compress::Brotli prior to 0.007 included a version of the brotli library prior to version 1.0.8, where an attacker controlling the input length of a "one-shot" decompression request to a script can trigger a crash, which happens when copying over chunks of data larger than 2 GiB. It is recommended to update your IO::Compress::Brotli module to 0.007 or later. If one cannot update, we recommend to use the "streaming" API as opposed to the "one-shot" API, and impose chunk size limits.
CVSS v3.1 Score
9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Other References
https://github.com/advisories/GHSA-5v8v-66v8-mwm7
https://github.com/google/brotli/commit/223d80cfbec8fd346e32906c732c8ede21f0cea6
https://github.com/google/brotli/pull/826
https://github.com/timlegge/perl-IO-Compress-Brotli/blob/8b44c83b23bb4658179e1494af4b725a1bc476bc/Changes#L52
https://nvd.nist.gov/vuln/detail/CVE-2020-8927
Frequently Asked Questions
What is CVE-2020-36846? +
A buffer overflow, as described in CVE-2020-8927, exists in the embedded Brotli library. Versions of IO::Compress::Brotli prior to 0.007 included a version of the brotli library prior to version 1.0.8, where an attacker controlling the input length of a "one-shot" decompression request to a script can trigger a crash, which happens when copying over chunks of data larger than 2 GiB. It is recommended to update your IO::Compress::Brotli module to 0.007 or later. If one cannot update, we recommend to use the "streaming" API as opposed to the "one-shot" API, and impose chunk size limits. It has a CVSS v3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2020-36846? +
CVE-2020-36846 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.
How do I check if I'm vulnerable to CVE-2020-36846? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.