CVE-2020-8927 | Buffer overflow in Brotli library

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.

Published: 2020-09-15 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-8927 is rated Moderate Risk (54.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.24%). EPSS rose +2.93% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-8927

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.31% 3.24% +2.93%
2 2025-11-21 1.34% 0.31% -1.03%
3 2025-11-18 — 1.34% —

Full EPSS history (26 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8927

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 2.5 [email protected]
6.4 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 4.9 [email protected]

Weakness enumeration for CVE-2020-8927

GitHub Security Advisory for CVE-2020-8927

GHSA-5v8v-66v8-mwm7 · Severity: medium · Ecosystem: rust — Integer overflow in the bundled Brotli C library

OS Trackers for CVE-2020-8927

vendor priority summary link
alpine medium CVE-2020-8927: 1 source package rows (brotli); 8 state rows across 8 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 8, open 0. https://security.alpinelinux.org/vuln/CVE-2020-8927
debian not yet assigned CVE-2020-8927 not yet assigned priority: Debian including 1 source packages (brotli), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-8927
redhat high — https://access.redhat.com/security/cve/CVE-2020-8927
suse medium CVE-2020-8927 severity moderate: SUSE including 566 source package names (0.0.17-1.1:libbrotlicommon1-1.0.7-3.3.1, 0.0.17-1.1:libbrotlidec1-1.0.7-3.3.1, …), 1484 product×package rows across 462 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (462 product lines)): Fixed 1172, Known Affected 231, Will Not Fix 43, Known Not Affected 38. https://www.suse.com/security/cve/CVE-2020-8927/
ubuntu medium CVE-2020-8927 medium priority: Ubuntu including 1 source packages (brotli), 5 status rows across 5 suites (bionic, focal, trusty, upstream, xenial): released 4, DNE 1. https://ubuntu.com/security/CVE-2020-8927

Affected software / configurations for CVE-2020-8927

Vendor Product Version Raw CPE
google brotli < 1.0.8 cpe:2.3:a:google:brotli:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
fedoraproject fedora 36 cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
microsoft .net >= 5.0, <= 5.0.14 cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*
microsoft .net_core >= 3.1, <= 3.1.22 cpe:2.3:a:microsoft:.net_core:*:*:*:*:*:*:*:*
microsoft powershell >= 7.0, < 7.0.9 cpe:2.3:a:microsoft:powershell:*:*:*:*:*:*:*:*
microsoft powershell >= 7.1, < 7.1.6 cpe:2.3:a:microsoft:powershell:*:*:*:*:*:*:*:*
microsoft powershell >= 7.2, < 7.2.2 cpe:2.3:a:microsoft:powershell:*:*:*:*:*:*:*:*
microsoft visual_studio_2019 >= 16.0, <= 16.11 cpe:2.3:a:microsoft:visual_studio_2019:*:*:*:*:*:*:*:*
microsoft visual_studio_2022 >= 17.0, <= 17.0.7 cpe:2.3:a:microsoft:visual_studio_2022:*:*:*:*:*:*:*:*
microsoft visual_studio_2022 17.1 cpe:2.3:a:microsoft:visual_studio_2022:17.1:*:*:*:*:*:*:*

References for CVE-2020-8927

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00108.html Mailing List Third Party Advisory
https://github.com/google/brotli/releases/tag/v1.0.9 Release Notes Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/12/msg00003.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/356JOYTWW4BWSZ42SEFLV7NYHL3S3AEH/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4TOGTZ2ZWDH662ZNFFSZVL3M5AJXV6JF/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J4E265WKWKYMK2RYYSIXBEGZTDY5IQE6/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M4VCDOJGL6BK3HB4XRD2WETBPYX2ITF6/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MMBKACMLSRX7JJSKBTR35UOEP2WFR6QP/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQLM7ABVCYJLF6JRPF3M3EBXW63GNC27/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W23CUADGMVMQQNFKHPHXVP7RPZJZNN6I/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WW62OZEY2GHJL4JCOLJRBSRETXDHMWRK/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZXEQ3GQVELA2T4HNZG7VPMS2HDVXMJRG/
https://usn.ubuntu.com/4568-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4801 Third Party Advisory
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