CVE-2020-28636 [Critical] | Out-of-bounds Read in Computational Geometry Al…

A code execution vulnerability exists in the Nef polygon-parsing functionality of CGAL libcgal CGAL-5.1.1. An oob read vulnerability exists in Nef_S2/SNC_io_parser.h SNC_io_parser::read_sloop() slh->twin() An attacker can provide malicious input to trigger this vulnerability.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	2.71%	2.88%	+0.17%
2	2026-05-31	0.69%	2.71%	+2.02%
3	2026-02-07	—	0.69%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

2.71%

2.88%

+0.17%

2026-05-31

0.69%

2.71%

+2.02%

2026-02-07

—

0.69%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/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: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: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.	3.9	5.9	[email protected]
10.0	3.0	CRITICAL	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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: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:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. 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.	3.9	6.0	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/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:L) Exploitation conditions are straightforward and predictable. 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.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/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: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: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.

3.9

5.9

[email protected]

10.0

3.0

CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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: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:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
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.

3.9

6.0

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/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:L): Exploitation conditions are straightforward and predictable.
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.

10.0

6.4

[email protected]

OS Trackers for CVE-2020-28636

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2020-28636 not yet assigned priority: Debian including 1 source packages (cgal), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-28636
`gentoo`	high	CVE-2020-28636: 1 GLSA(s) (202305-34), 1 atom(s) (sci-mathematics/cgal); latest impact high.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-28636
`ubuntu`	medium	CVE-2020-28636 medium priority: Ubuntu including 1 source packages (cgal), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 9, needs-triage 4, ignored 2, released 1.	https://ubuntu.com/security/CVE-2020-28636

Affected software / configurations for CVE-2020-28636

Vendor	Product	Version	Raw CPE
cgal	computational_geometry_algorithms_library	5.1.1	cpe:2.3:a:cgal:computational_geometry_algorithms_library:5.1.1:::::::*
fedoraproject	fedora	33	cpe:2.3:o:fedoraproject:fedora:33:::::::*
fedoraproject	fedora	34	cpe:2.3:o:fedoraproject:fedora:34:::::::*
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:::::::*

References for CVE-2020-28636

URL	Tags
https://lists.debian.org/debian-lts-announce/2021/05/msg00002.html	Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/12/msg00011.html	Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E4J344OKKDLPRN422OYRR46HDEN6MM6P/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NB5SF5OJR2DSV7CC6U7FVW5VJSJO5EKV/
https://security.gentoo.org/glsa/202305-34
https://talosintelligence.com/vulnerability_reports/TALOS-2020-1225	Technical Description Third Party Advisory

URL

CVE-2020-28636

Exploit prediction scoring system (EPSS) score for CVE-2020-28636

Common vulnerability scoring system (CVSS) metrics for CVE-2020-28636

Weakness enumeration for CVE-2020-28636

OS Trackers for CVE-2020-28636

Affected software / configurations for CVE-2020-28636

References for CVE-2020-28636