CVE-2020-8927 is a medium-severity (CVSS 6.5) CWE-130 vulnerability in compu-brotli-sys. A fix is available for compu-brotli-sys — see the affected versions and patch details below.
Integer overflow in the bundled Brotli C library
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2020-8927.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
compu-brotli-sys.NETMicrosoft.NETCore.App.Runtime.linux-arm.NETMicrosoft.NETCore.App.Runtime.linux-arm64.NETMicrosoft.NETCore.App.Runtime.linux-musl-arm64.NETMicrosoft.NETCore.App.Runtime.linux-x64.NETMicrosoft.NETCore.App.Runtime.osx-x64.NETMicrosoft.NETCore.App.Runtime.win-arm.NETMicrosoft.NETCore.App.Runtime.win-arm64+141 moreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io, NuGet packages — download data is not available via public APIs for these ecosystems.
Description
A buffer overflow exists in the Brotli library versions prior to 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 Brotli library to 1.0.8 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | compu-brotli-sys | all versions | 1.0.9cargo update -p compu-brotli-sys --precise 1.0.9 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.linux-arm | ≥ 3.0.0&&< 3.1.23 | 3.1.23dotnet add package Microsoft.NETCore.App.Runtime.linux-arm --version 3.1.23 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.linux-arm64 | ≥ 3.0.0&&< 3.1.23 | 3.1.23dotnet add package Microsoft.NETCore.App.Runtime.linux-arm64 --version 3.1.23 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.linux-musl-arm64 | ≥ 3.0.0&&< 3.1.23 | 3.1.23dotnet add package Microsoft.NETCore.App.Runtime.linux-musl-arm64 --version 3.1.23 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.linux-x64 | ≥ 3.0.0&&< 3.1.23 | 3.1.23dotnet add package Microsoft.NETCore.App.Runtime.linux-x64 --version 3.1.23 |
| .NETNuGet | Microsoft.NETCore.App.Runtime.osx-x64 | ≥ 3.0.0&&< 3.1.23 | 3.1.23dotnet add package Microsoft.NETCore.App.Runtime.osx-x64 --version 3.1.23 |
Affected Products
ubuntu linuxcanonicaldebian linuxdebianfedorafedoraprojectbrotligoogle.netmicrosoft.net coremicrosoftDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for compu-brotli-sys, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update compu-brotli-sys to 1.0.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-8927 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw can be mitigated by using Streaming API instead of the One-Shot API and imposing chunk size limitations.Source: Red Hat security advisory for CVE-2020-8927 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| .NET Core on Red Hat Enterprise Linux | rh-dotnet31-dotnet-0:3.1.417-1.el7_9 | RHSA-2022:0829 |
| .NET Core on Red Hat Enterprise Linux | rh-dotnet50-dotnet-0:5.0.212-1.el7_9 | RHSA-2022:0828 |
| Red Hat Enterprise Linux 8 | brotli-0:1.0.6-3.el8 | RHSA-2021:1702 |
| Red Hat Enterprise Linux 8 | dotnet3.1-0:3.1.417-1.el8_5 | RHSA-2022:0827 |
| Red Hat Enterprise Linux 8 | dotnet5.0-0:5.0.212-1.el8_5 | RHSA-2022:0830 |
Frequently Asked Questions
Is CVE-2020-8927 in your dependencies?
Find it across crates.io, NuGet, PyPI, including transitive dependencies.