CVE-2020-5254 [Low] | Memory Corruption in Nethack

CVE-2020-5254 is rated Low Risk (32.3/100): CVSS Low severity, with medium exploitation likelihood (EPSS 1.13%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	9.28%	1.13%	-8.15%
2	2025-11-21	6.02%	9.28%	+3.26%
3	2025-11-18	—	6.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

9.28%

1.13%

-8.15%

2025-11-21

6.02%

9.28%

+3.26%

2025-11-18

—

6.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
3.9	3.1	LOW	`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	0.8	2.7	[email protected]
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

3.9

3.1

LOW

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

0.8

2.7

[email protected]

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-2020-5254

vendor	priority	summary	link
`alpine`	high	CVE-2020-5254: 1 source package rows (nethack); 2 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 2.	https://security.alpinelinux.org/vuln/CVE-2020-5254
`debian`	not yet assigned	CVE-2020-5254 not yet assigned priority: Debian including 1 source packages (nethack), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2020-5254
`ubuntu`	medium	CVE-2020-5254 medium priority: Ubuntu including 1 source packages (nethack), 17 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 13, needed 2, DNE 1, ignored 1.	https://ubuntu.com/security/CVE-2020-5254

Affected software / configurations for CVE-2020-5254

Vendor	Product	Version	Raw CPE
nethack	nethack	>= 3.6.1, < 3.6.6	cpe:2.3:a:nethack:nethack::::::::

References for CVE-2020-5254

URL	Tags
https://github.com/NetHack/NetHack/security/advisories/GHSA-2ch6-6r8h-m2p9	Vendor Advisory

URL

CVE-2020-5254 | NetHack hilite_status parsing privilege escalation

Exploit prediction scoring system (EPSS) score for CVE-2020-5254

Common vulnerability scoring system (CVSS) metrics for CVE-2020-5254

Weakness enumeration for CVE-2020-5254

OS Trackers for CVE-2020-5254

Affected software / configurations for CVE-2020-5254

References for CVE-2020-5254