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Fencer Vulns
high 8.8

CVE-2023-4863 kev in the critical feed json

libwebp: OOB write in BuildHuffmanTable

published 2023-09-12 3 y ago modified 2026-09-10 1 mo ago also CVE-2023-5129 , EUVD-2023-2533 , GHSA-j7hp-h8jx-5ppr , JLSEC-2026-441 , PYSEC-2026-1794 , RUSTSEC-2023-0060 , RUSTSEC-2023-0061

cvss
8.8
version 3.1, CNA
cisa kev
Exploited
added 2023-09-13
epss
100.0%
EPSS 100.0% chance of exploitation in 30 days, percentile 99.9%
public exploits
0
none known

Summary

Heap buffer overflow in libwebp in Google Chrome prior to 116.0.5845.187 and libwebp 1.3.2 allowed a remote attacker to perform an out of bounds memory write via a crafted HTML page. (Chromium security severity: Critical)

Patch / fix

cisa required action Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  • crates.io libwebp-sys2 0.1.8
  • crates.io libwebp-sys 0.9.3
  • npm electron 22.3.24, 24.8.3, 25.8.1, 26.2.1, 27.0.0-beta.2
  • nuget SkiaSharp 2.88.6
  • go github.com/chai2010/webp 0.0.0-20250406010349-76805d5a8860, 1.1.2-0.20250406010349-76805d5a8860, 1.4.0
  • pypi pillow 10.0.1
  • crates.io webp 0.2.6
  • nuget magick.net-q16-anycpu 13.3.0
  • nuget magick.net-q16-hdri-anycpu 13.3.0
  • nuget magick.net-q16-x64 13.3.0
  • nuget magick.net-q8-anycpu 13.3.0
  • nuget magick.net-q8-openmp-x64 13.3.0
  • nuget magick.net-q8-x64 13.3.0
  • julia libwebp_jll 1.3.2+0
  • google chrome 116.0.5845.187
  • mozilla firefox 102.15.1, 115.2.1, 117.0.1
  • mozilla thunderbird 102.15.1, 115.2.2
  • microsoft edge_chromium 116.0.1938.81
  • microsoft teams 1.6.00.26463, 1.6.00.26474
  • microsoft webp_image_extension 1.0.62681.0
  • webmproject libwebp 1.3.2
  • bentley seequent_leapfrog 2023.2
  • bandisoft honeyview 5.51
  • libwebp Debian 12 1.2.4-0.2+deb12u1
  • libwebp Debian 14, Debian 13 1.2.4-0.3
  • chromium Debian 14, Debian 13, Debian 12 117.0.5938.62-1
  • firefox-esr Debian 12 102.15.1esr-1~deb12u1
  • firefox-esr Debian 14, Debian 13 115.2.1esr-1
  • thunderbird Debian 12 1:102.15.1-1~deb12u1
  • thunderbird Debian 14, Debian 13 1:115.2.2-1

debian advisories DEBIAN-CVE-2023-4863

  • firefox Ubuntu 20.04 LTS 117.0.1+build2-0ubuntu0.20.04.1
  • libwebp Ubuntu 20.04 LTS 0.6.1-2ubuntu0.20.04.3
  • libwebp Ubuntu 22.04 LTS 1.2.2-2ubuntu0.22.04.2
  • thunderbird Ubuntu 20.04 LTS 1:102.15.1+build1-0ubuntu0.20.04.1
  • thunderbird Ubuntu 22.04 LTS 1:102.15.1+build1-0ubuntu0.22.04.1
  • libwebp Ubuntu Pro 18.04 LTS 0.6.1-2ubuntu0.18.04.2+esm1

ubuntu advisories UBUNTU-CVE-2023-4863

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libwebp RHEL 9 1.2.0-7.el9_2
  • libwebp-tools RHEL 9 1.2.0-7.el9_2
  • firefox RHEL 8 102.15.1-1.el8_8
  • thunderbird RHEL 8 102.15.1-1.el8_8
  • libwebp RHEL 8 1.0.0-8.el8_8.1
  • thunderbird RHEL 7 102.15.1-1.el7_9
  • firefox RHEL 9 102.15.1-1.el9_2
  • firefox-x11 RHEL 9 102.15.1-1.el9_2

red hat advisories RHSA-2023:5214RHSA-2023:5223RHSA-2023:5222RHSA-2023:5185RHSA-2023:5198RHSA-2023:5202

  • libwebp SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE Workstation Extension 15 SP5 +5 more 0.5.0-150000.3.14.1
  • libwebp SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 +5 more 0.4.3-4.15.1
  • MozillaThunderbird SLE Workstation Extension 15 SP5, SLE Workstation Extension 15 SP4, SLE Module for Package Hub 15 SP5 +3 more 115.2.2-150200.8.130.1
  • libwebp SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +13 more 1.0.3-150200.3.10.1
  • MozillaFirefox SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 115.2.1-112.179.1
  • MozillaFirefox SLES for SAP 15 SP3, SLES for SAP 15 SP2, SLES 15 SP3-LTSS +9 more 115.2.1-150200.152.105.1
  • MozillaFirefox SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 115.2.1-150000.150.103.1

suse advisories SUSE-SU-2023:3829-1SUSE-SU-2023:3794-1SUSE-SU-2023:3664-1SUSE-SU-2023:3634-1SUSE-SU-2023:3626-1SUSE-SU-2023:3610-1

  • dssim openSUSE Tumbleweed 3.5.1-1.1
  • python-imagecodecs openSUSE Tumbleweed 2026.3.6-2.10
  • afl openSUSE Tumbleweed 5.00c-1.1
  • firefox-esr openSUSE Tumbleweed 128.5.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 117.0.1-1.1
  • MozillaThunderbird openSUSE Tumbleweed 115.2.2-1.1
  • chromium openSUSE Tumbleweed 116.0.5845.187-1.1
  • libwebp openSUSE Tumbleweed 1.3.1-2.1

opensuse advisories openSUSE-SU-2026:12177-1openSUSE-SU-2026:12010-1openSUSE-SU-2026:10991-1openSUSE-SU-2024:14572-1openSUSE-SU-2024:13227-1openSUSE-SU-2024:13228-1

  • libwebp AlmaLinux 8 1.0.0-8.el8_8.1
  • libwebp AlmaLinux 9 1.2.0-7.el9_2
  • libwebp-tools AlmaLinux 9 1.2.0-7.el9_2
  • thunderbird AlmaLinux 9 102.15.1-1.el9_2.alma
  • firefox AlmaLinux 8 102.15.1-1.el8_8.alma
  • firefox AlmaLinux 9 102.15.1-1.el9_2.alma
  • firefox-x11 AlmaLinux 9 102.15.1-1.el9_2.alma
  • thunderbird AlmaLinux 8 102.15.1-1.el8_8.alma

almalinux advisories ALSA-2023:5309ALSA-2023:5214ALSA-2023:5224ALSA-2023:5184ALSA-2023:5200ALSA-2023:5201

  • libwebp Rocky Linux 9 1.2.0-7.el9_2
  • thunderbird Rocky Linux 8 102.15.1-1.el8_8
  • libwebp Rocky Linux 8 1.0.0-8.el8_8.1
  • firefox Rocky Linux 8 102.15.1-1.el8_8

rocky linux advisories RLSA-2023:5214RLSA-2023:5201RLSA-2023:5309RLSA-2023:5184

  • libwebp Alpine 3.15 1.2.2-r2
  • libwebp Alpine 3.16 1.2.3-r2
  • libwebp Alpine 3.17 1.2.4-r3
  • libwebp Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 1.3.1-r1
  • chromium Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 116.0.5845.187-r0
  • firefox-esr Alpine 3.23, Alpine 3.22, Alpine 3.21 +3 more 115.2.1-r0
  • qt5-qtwebengine Alpine 3.18 5.15.13-r7
  • qt5-qtwebengine Alpine 3.23, Alpine 3.22, Alpine 3.21 +2 more 5.15.15-r1

alpine advisories ALPINE-CVE-2023-4863

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libwebp CBL-Mariner 2.0 1.3.2-1

azure linux advisories AZL-29758

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-4863 updated cvss 9.6

libwebp: Heap buffer overflow in WebP Codec

  • Red Hat Enterprise Linux 6 firefox
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) libwebp 1.0.0-8.el8_8.1, firefox 102.15.1-1.el8_8, thunderbird 102.15.1-1.el8_8
    fixed: vendor fix RHSA-2023:5184
  • Red Hat Enterprise Linux AppStream (v. 9) libwebp 1.2.0-7.el9_2, firefox 102.15.1-1.el9_2, firefox-x11 102.15.1-1.el9_2, thunderbird 102.15.1-1.el9_2, rhel9/firefox-flatpak flatpak-9020020231006113910.2, rhel9/thunderbird-flatpak flatpak-9020020231006114109.1
    fixed: vendor fix RHSA-2023:5200
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) libwebp 1.0.0-7.el8_2.1, firefox 102.15.1-1.el8_2, thunderbird 102.15.1-1.el8_2
    fixed: vendor fix RHSA-2023:5187
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) libwebp 1.0.0-7.el8_4.1, firefox 102.15.1-1.el8_4, thunderbird 102.15.1-1.el8_4
    fixed: vendor fix RHSA-2023:5192
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) firefox 102.15.1-1.el8_1, libwebp 1.0.0-5.2.el8_1.1, thunderbird 102.15.1-1.el8_1
    fixed: vendor fix RHSA-2023:5183
  • Red Hat Enterprise Linux AppStream E4S (v. 8.2) libwebp 1.0.0-7.el8_2.1, firefox 102.15.1-1.el8_2, thunderbird 102.15.1-1.el8_2
    fixed: vendor fix RHSA-2023:5187
  • Red Hat Enterprise Linux AppStream E4S (v.8.4) libwebp 1.0.0-7.el8_4.1, firefox 102.15.1-1.el8_4, thunderbird 102.15.1-1.el8_4
    fixed: vendor fix RHSA-2023:5192
show 8 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) libwebp 1.0.0-7.el8_6.1, firefox 102.15.1-1.el8_6, thunderbird 102.15.1-1.el8_6
    fixed: vendor fix RHSA-2023:5198
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) libwebp 1.2.0-6.el9_0, firefox 102.15.1-1.el9_0, thunderbird 102.15.1-1.el9_0
    fixed: vendor fix RHSA-2023:5205
  • Red Hat Enterprise Linux AppStream TUS (v. 8.2) libwebp 1.0.0-7.el8_2.1, firefox 102.15.1-1.el8_2, thunderbird 102.15.1-1.el8_2
    fixed: vendor fix RHSA-2023:5187
  • Red Hat Enterprise Linux AppStream TUS (v.8.4) libwebp 1.0.0-7.el8_4.1, firefox 102.15.1-1.el8_4, thunderbird 102.15.1-1.el8_4
    fixed: vendor fix RHSA-2023:5192
  • Red Hat Enterprise Linux Client (v. 7) firefox 102.15.1-1.el7_9, thunderbird 102.15.1-1.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) firefox 102.15.1-1.el7_9
    fixed: vendor fix RHSA-2023:5197
  • Red Hat Enterprise Linux CRB (v. 9) libwebp-tools 1.2.0-7.el9_2
    fixed: vendor fix RHSA-2023:5214
  • Red Hat Enterprise Linux Server (v. 7) firefox 102.15.1-1.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 102.15.1-1.el7_9, thunderbird 102.15.1-1.el7_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 102.15.1-1.el7_9, thunderbird 102.15.1-1.el7_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 102.15.1-1.el7_9
    fixed: vendor fix RHSA-2023:5197
  • Red Hat Enterprise Linux 7 libwebp, libwebp-java, libwebp-tools
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-300-02 updated cvss 8.2

Mitsubishi Electric GENESIS, GENESIS64, ICONICS Suite, Hyper Historian, AnalytiX, MobileHMI, IoTWorX, MC Works64, GENESIS32 and BizViz

  • Mitsubishi Electric GENESIS64 >=10.97, <=10.97.2 Mitsubishi Electric Iconics Digital Solutions GENESIS64 >=10.97, <=10.97.2 Mitsubishi Electric Iconics Digital Solutions ICONICS Suite >=10.97, <=10.97.2 Mitsubishi Electric ICONICS Suite >=10.97, <=10.97.2
    affected: vendor fix, mitigation iconicsinc.my.site.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-23-320-11 updated cvss 7.5

Siemens Mendix Studio Pro

  • Siemens Mendix Studio Pro 7 <V7.23.37
    affected: fixed in V7.23.37 docs.mendix.com
  • Siemens Mendix Studio Pro 8 <V8.18.27
    affected: fixed in V8.18.27 docs.mendix.com
  • Siemens Mendix Studio Pro 9 <V9.24.0
    affected: fixed in V9.24.0 docs.mendix.com
  • Siemens Mendix Studio Pro 10 <V10.3.1
    affected: fixed in V10.3.1 docs.mendix.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Timeline

  1. Found exploited as a 0-day (Project Zero)
  2. 0-day patched (Project Zero)
  3. Published
  4. Added to CISA KEV
  5. CISA patch deadline
  6. CISA SSVC: exploitation active

Known exploited

Added
3 y ago
Patch by
2023-10-04 (3 y ago)
Ransomware
Not known
Required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vendor, product
Google, Chromium WebP
CISA name
Google Chromium WebP Heap-Based Buffer Overflow Vulnerability

Zero-day

Detected in real attacks while still unknown to the vendor and the public, per Google Project Zero's 0day In-the-Wild tracker.

Found
2023-09-06
Patched
2023-09-12
Details
project zero tracker

ATT&CK techniques

How it is exploited and what it leads to, in MITRE ATT&CK terms.

  • T1456 Drive-By Compromise exploitation, mobile
  • T1658 Exploitation for Client Execution primary impact, mobile

kev release 2025-07-28, att&ck v16.1. KEV to ATT&CK mappings by the MITRE Center for Threat-Informed Defense (Mappings Explorer, Apache-2.0). © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. Terms of use

CISA SSVC

Exploitation
Active, exploited in the wild
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

99.98% chance of exploitation in the next 30 days, higher than 99.9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • stackdiary.com https://stackdiary.com/critical-vulnerability-in-webp-codec-cve-2023-4863/ referenced PoC, tagged "exploit" by a source, unverified
  • news.ycombinator.com https://news.ycombinator.com/item?id=37478403 referenced PoC, tagged "exploit" by a source, unverified
  • blog.isosceles.com https://blog.isosceles.com/the-webp-0day/ referenced PoC, tagged "exploit" by a source, unverified
  • sethmlarson.dev https://sethmlarson.dev/security-developer-in-residence-weekly-report-16 referenced PoC, tagged "exploit" by a source, unverified
  • vicarius.io https://www.vicarius.io/vsociety/posts/zero-day-webp-vulnerability-cve-2023-4863 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
crates.io libwebp-sys2
<0.1.8
>=0.0.0-0, <0.1.8
0.1.8
crates.io libwebp-sys
<0.9.3
>=0.0.0-0, <0.9.3
0.9.3
npm electron
>=22.0.0, <22.3.24
>=24.0.0, <24.8.3
>=25.0.0, <25.8.1
>=26.0.0, <26.2.1
>=27.0.0-beta.1, <27.0.0-beta.2
22.3.24
24.8.3
25.8.1
26.2.1
27.0.0-beta.2
nuget SkiaSharp
>=2.0.0, <2.88.6
2.88.6
go github.com/chai2010/webp
>=1.1.2, <1.4.0
<0.0.0-20250406010349-76805d5a8860
>=0.0.0, <1.1.2-0.20250406010349-76805d5a8860
1.4.0
0.0.0-20250406010349-76805d5a8860
1.1.2-0.20250406010349-76805d5a8860
pypi pillow
<10.0.1
10.0.1
crates.io webp
<0.2.6
0.2.6
nuget magick.net-q16-anycpu
<13.3.0
13.3.0
nuget magick.net-q16-hdri-anycpu
<13.3.0
13.3.0
nuget magick.net-q16-x64
<13.3.0
13.3.0
nuget magick.net-q8-anycpu
<13.3.0
13.3.0
nuget magick.net-q8-openmp-x64
<13.3.0
13.3.0
nuget magick.net-q8-x64
<13.3.0
13.3.0
julia libwebp_jll
<1.3.2+0
1.3.2+0

Affected products

  • Google Chrome
  • Google libwebp

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.