CVE-2020-36331Network attack vector

Memory disclosure and service interruption via oversized chunks

Published May 21, 2021 · Updated Aug 4, 2024

Out-of-bounds read in Google libwebp before 1.0.1 allows remote attackers to read process memory or interrupt services via crafted WebP data. The mux reader adds header padding to an unvalidated 32-bit RIFF chunk length, allowing the size calculation to wrap before its bounds check. Processing attacker-controlled WebP data is required; the over-read affects confidentiality or terminates the consuming process, with no reported write primitive.

CVSS severity9.1
Critical
EPSS probability2.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds read in Google libwebp before 1.0.1 allows remote attackers to read process memory or interrupt services via crafted WebP data. The mux reader adds header padding to an unvalidated 32-bit RIFF chunk length, allowing the size calculation to wrap before its bounds check. Processing attacker-controlled WebP data is required; the over-read affects confidentiality or terminates the consuming process, with no reported write primitive.

The record

CVE
CVE-2020-36331
Published
May 21, 2021
Updated
Aug 4, 2024
Vendor
Google
Product
libwebp
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=libwebp 1.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Google · libwebpversion=libwebp 1.0.1

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:P
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo