CVE-2020-8927: Buffer overflow in Brotli library
Noroxi assessment
Priority: Monitor (action score 27/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 3.2% (FIRST EPSS); higher than 88.1% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: aspnetcore-runtime-3.1 (AlmaLinux:8) 3.1.23-1.el8_5; aspnetcore-runtime-5.0 (AlmaLinux:8) 5.0.15-1.el8_5; aspnetcore-targeting-pack-3.1 (AlmaLinux:8) 3.1.23-1.el8_5.
- Mentioned 4 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to aspnetcore-runtime-3.1 (AlmaLinux:8) 3.1.23-1.el8_5; aspnetcore-runtime-5.0 (AlmaLinux:8) 5.0.15-1.el8_5; aspnetcore-targeting-pack-3.1 (AlmaLinux:8) 3.1.23-1.el8_5 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- BDU:2021-01775
- GHSA-5v8v-66v8-mwm7
- ALSA-2021:1702
- ALSA-2022:0827
- ALSA-2022:0830
- DLA-2476-1
- DSA-4801-1
- GO-2025-3726
- openSUSE-SU-2020:1578-1
- openSUSE-SU-2021:3942-1
- openSUSE-SU-2024:11708-1
- openSUSE-SU-2026:11988-1
- PYSEC-2020-29
- RHSA-2021:1702
- RHSA-2022:0827
- RHSA-2022:0828
- RHSA-2022:0829
- RHSA-2022:0830
- RLSA-2021:1702
- RLSA-2022:0827
- Published
- Sep 15, 2020
- Updated
- Jun 16, 2026
- EPSS
- 3.2% · 88th percentile
- CWE
- CWE-130
Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 6.5
- CNA · Google
- 5.3
- 1.2 point gap
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| brotli | cpe:2.3:a:google:brotli | |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| microsoft | .net | cpe:2.3:a:microsoft:.net |
| microsoft | .net core | cpe:2.3:a:microsoft:.net_core |
| microsoft | powershell | cpe:2.3:a:microsoft:powershell |
| microsoft | visual studio 2019 | cpe:2.3:a:microsoft:visual_studio_2019 |
| microsoft | visual studio 2022 | cpe:2.3:a:microsoft:visual_studio_2022 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- canonical ubuntu linux20.04
- debian debian linux10.0
- debian debian linux9.0
- fedoraproject fedora31
- fedoraproject fedora32
- fedoraproject fedora33
- fedoraproject fedora34
- fedoraproject fedora35
- fedoraproject fedora36
- google brotlibefore 1.0.8
- microsoft .net5.0 and later · up to 5.0.14 inclusive
- microsoft .net core3.1 and later · up to 3.1.22 inclusive
- microsoft powershell7.0 and later · before 7.0.9
- microsoft powershell7.1 and later · before 7.1.6
- microsoft powershell7.2 and later · before 7.2.2
- microsoft visual studio 201916.0 and later · up to 16.11 inclusive
- microsoft visual studio 202217.0 and later · up to 17.0.7 inclusive
- microsoft visual studio 202217.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Google). Independent of NVD's CPE analysis and usually ahead of it.
Google LLC Brotli
- stable and later · up to and including 1.0.7affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | aspnetcore-runtime-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | aspnetcore-runtime-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | aspnetcore-targeting-pack-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | aspnetcore-targeting-pack-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | brotli | before 1.0.6-3.el8 | 1.0.6-3.el8 |
| AlmaLinux:8 | brotli-devel | before 1.0.6-3.el8 | 1.0.6-3.el8 |
| AlmaLinux:8 | dotnet-apphost-pack-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | dotnet-apphost-pack-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | dotnet-hostfxr-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | dotnet-hostfxr-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | dotnet-runtime-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | dotnet-runtime-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | dotnet-sdk-3.1 | before 3.1.417-1.el8_5 | 3.1.417-1.el8_5 |
| AlmaLinux:8 | dotnet-sdk-3.1-source-built-artifacts | before 3.1.417-1.el8_5 | 3.1.417-1.el8_5 |
| AlmaLinux:8 | dotnet-sdk-5.0 | before 5.0.212-1.el8_5 | 5.0.212-1.el8_5 |
| AlmaLinux:8 | dotnet-sdk-5.0-source-built-artifacts | before 5.0.212-1.el8_5 | 5.0.212-1.el8_5 |
| AlmaLinux:8 | dotnet-targeting-pack-3.1 | before 3.1.23-1.el8_5 | 3.1.23-1.el8_5 |
| AlmaLinux:8 | dotnet-targeting-pack-5.0 | before 5.0.15-1.el8_5 | 5.0.15-1.el8_5 |
| AlmaLinux:8 | dotnet-templates-3.1 | before 3.1.417-1.el8_5 | 3.1.417-1.el8_5 |
| AlmaLinux:8 | dotnet-templates-5.0 | before 5.0.212-1.el8_5 | 5.0.212-1.el8_5 |
| AlmaLinux:8 | python3-brotli | before 1.0.6-3.el8 | 1.0.6-3.el8 |
| Alpine:v3.12 | brotli | before 1.0.9-r0 | 1.0.9-r0 |
| crates.io | brotli-sys | from 0.0.0-0 | — |
| crates.io | compu-brotli-sys | from 0.0.0-0 · before 1.0.9 | 1.0.9 |
+96
Same product
google: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-111497Out-of-Bounds Write in Google Brotli Decoder46Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:aspnetcore-runtime-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:aspnetcore-targeting-pack-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:brotli | 1.0.6-3.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:brotli-devel | 1.0.6-3.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-apphost-pack-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-hostfxr-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-runtime-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-sdk-3.1 | 3.1.417-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-sdk-3.1-source-built-artifacts | 3.1.417-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-targeting-pack-3.1 | 3.1.23-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:dotnet-templates-3.1 | 3.1.417-1.el8_5 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python3-brotli | 1.0.6-3.el8 · AlmaLinux:8 | Package registry (OSV) |
| alpine:brotli | 1.0.9-r0 · Alpine:v3.12 | Package registry (OSV) |
| crates.io:compu-brotli-sys | 1.0.9 | Package registry (OSV) |
| debian:brotli | 1.0.9-1 · Debian:12 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.linux-x64.Cross.android-arm | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.linux-x64.Cross.android-arm64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.linux-x64.Cross.android-x64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.linux-x64.Cross.android-x86 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.linux-x64.Cross.browser-wasm | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.android-arm | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.android-arm64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.android-x64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.android-x86 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.browser-wasm | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.ios-arm | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.ios-arm64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.iossimulator-arm64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.iossimulator-x64 | 6.0.3 | Package registry (OSV) |
| NuGet:Microsoft.NETCore.App.Runtime.AOT.osx-x64.Cross.iossimulator-x86 | 6.0.3 | Package registry (OSV) |
+90
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-22-0552 · Aug 15, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0217 · Mar 11, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0020 · Jan 10, 2022(IBM Güvenlik Bülteni)
- TR-21-0772 · Sep 23, 2021(RedHat Güvenlik Zafiyeti)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- low · data or configuration can be modified
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- Low
- Availability impact
- Low
Weakness class (CWE)
CWE-130 · Improper Handling of Length Parameter InconsistencyCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (13 more)Show less
- github.com/google/brotli/releases/tag/v1.0.9
- lists.debian.org/debian-lts-announce/2020/12/msg00003.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/356JOYTWW4BWSZ42SEFLV7NYHL3S3AEH/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4TOGTZ2ZWDH662ZNFFSZVL3M5AJXV6JF/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J4E265WKWKYMK2RYYSIXBEGZTDY5IQE6/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M4VCDOJGL6BK3HB4XRD2WETBPYX2ITF6/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MMBKACMLSRX7JJSKBTR35UOEP2WFR6QP/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQLM7ABVCYJLF6JRPF3M3EBXW63GNC27/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W23CUADGMVMQQNFKHPHXVP7RPZJZNN6I/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WW62OZEY2GHJL4JCOLJRBSRETXDHMWRK/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZXEQ3GQVELA2T4HNZG7VPMS2HDVXMJRG/
- usn.ubuntu.com/4568-1/
- www.debian.org/security/2020/dsa-4801
Vendor advisories and official records. Exploit/PoC links are deliberately left out.