CVE-2020-11538 [High] | Out-of-bounds Read in Pillow

CVE-2020-11538 is rated Moderate Risk (61.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.51%). Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-26	2.43%	2.51%	+0.09%
2	2026-06-23	2.09%	2.43%	+0.33%
3	2026-06-15	—	2.09%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-26

2.43%

2.51%

+0.09%

2026-06-23

2.09%

2.43%

+0.33%

2026-06-15

—

2.09%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.1	3.1	HIGH	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. 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:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.2	5.9	[email protected]
6.8	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/I:P/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	8.6	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.1

3.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.2

5.9

[email protected]

6.8

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

6.4

[email protected]

OS Trackers for CVE-2020-11538

vendor	priority	summary	link
`debian`	low	CVE-2020-11538 low priority: Debian including 1 source packages (pillow), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-11538
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2020-11538
`suse`	high	CVE-2020-11538 severity important: SUSE including 139 source package names (ansible1-1.9.6-9.7.2, ardana-ansible-9.0+git.1591138508.e269bdb-3.22.2, …), 245 product×package rows across 9 product lines (HPE Helion OpenStack 8, HPE Helion OpenStack Cloud 8, … (9 product lines)): Fixed 239, Known Not Affected 6.	https://www.suse.com/security/cve/CVE-2020-11538/
`ubuntu`	low	CVE-2020-11538 low priority: Ubuntu including 3 source packages (pillow, pillow-python2, python-imaging), 49 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 28, not-affected 13, needs-triage 3, released 3, ignored 2.	https://ubuntu.com/security/CVE-2020-11538

Affected software / configurations for CVE-2020-11538

Vendor	Product	Version	Raw CPE
python	pillow	<= 7.0.0	cpe:2.3:a:python:pillow::::::::
fedoraproject	fedora	31	cpe:2.3:o:fedoraproject:fedora:31:::::::*
fedoraproject	fedora	32	cpe:2.3:o:fedoraproject:fedora:32:::::::*
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:::

References for CVE-2020-11538

URL	Tags
https://github.com/python-pillow/Pillow/pull/4504	Issue Tracking Patch
https://github.com/python-pillow/Pillow/pull/4538	Issue Tracking Patch
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BEBCPE4F2VHTIT6EZA2YZQZLPVDEBJGD/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HOKHNWV2VS5GESY7IBD237E7C6T3I427/
https://pillow.readthedocs.io/en/stable/releasenotes/7.1.0.html	Product
https://pillow.readthedocs.io/en/stable/releasenotes/index.html	Release Notes
https://usn.ubuntu.com/4430-1/	Third Party Advisory
https://usn.ubuntu.com/4430-2/	Third Party Advisory

URL

CVE-2020-11538

Exploit prediction scoring system (EPSS) score for CVE-2020-11538

Common vulnerability scoring system (CVSS) metrics for CVE-2020-11538

Weakness enumeration for CVE-2020-11538

GitHub Security Advisory for CVE-2020-11538

OS Trackers for CVE-2020-11538

Affected software / configurations for CVE-2020-11538

References for CVE-2020-11538