CVE-2020-36330 [Critical] | Out-of-bounds Read in Libwebp

A flaw was found in libwebp in versions before 1.0.1. An out-of-bounds read was found in function ChunkVerifyAndAssign. The highest threat from this vulnerability is to data confidentiality and to the service availability.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-05	0.16%	0.40%	+0.24%
2	2025-11-21	1.40%	0.16%	-1.23%
3	2025-11-18	—	1.40%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-05

0.16%

0.40%

+0.24%

2025-11-21

1.40%

0.16%

-1.23%

2025-11-18

—

1.40%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.1	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H` 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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.2	[email protected]
6.4	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:P/I:N/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:P) Partial confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	4.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.1

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H 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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.2

[email protected]

6.4

2.0

MEDIUM

AV:N/AC:L/Au:N/C:P/I:N/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:P): Partial confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

4.9

[email protected]

OS Trackers for CVE-2020-36330

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2020-36330 not yet assigned priority: Debian including 1 source packages (libwebp), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-36330
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2020-36330
`suse`	high	CVE-2020-36330 severity important: SUSE including 255 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 429 product×package rows across 53 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (53 product lines)): Known Affected 231, Fixed 191, Known Not Affected 7.	https://www.suse.com/security/cve/CVE-2020-36330/
`ubuntu`	medium	CVE-2020-36330 medium priority: Ubuntu including 1 source packages (libwebp), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): released 8, needs-triage 1.	https://ubuntu.com/security/CVE-2020-36330

Affected software / configurations for CVE-2020-36330

Vendor	Product	Version	Raw CPE
webmproject	libwebp	< 1.0.1	cpe:2.3:a:webmproject:libwebp::::::::
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:::::::*
redhat	enterprise_linux	8.0	cpe:2.3:o:redhat:enterprise_linux:8.0:::::::*
netapp	ontap_select_deploy_administration_utility	—	cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:::::::*
apple	ipados	< 14.7	cpe:2.3:o:apple:ipados::::::::
apple	iphone_os	< 14.7	cpe:2.3:o:apple:iphone_os::::::::

References for CVE-2020-36330

URL	Tags
http://seclists.org/fulldisclosure/2021/Jul/54	Mailing List Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1956853	Issue Tracking Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00005.html	Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/06/msg00006.html	Mailing List Third Party Advisory
https://security.netapp.com/advisory/ntap-20211104-0004/	Third Party Advisory
https://support.apple.com/kb/HT212601	Not Applicable
https://www.debian.org/security/2021/dsa-4930	Third Party Advisory

URL

CVE-2020-36330

Exploit prediction scoring system (EPSS) score for CVE-2020-36330

Common vulnerability scoring system (CVSS) metrics for CVE-2020-36330

Weakness enumeration for CVE-2020-36330

OS Trackers for CVE-2020-36330

Affected software / configurations for CVE-2020-36330

References for CVE-2020-36330