CVE-2020-5213

Code execution via unbounded SYMBOL option decoding

Published Jan 28, 2020 · Updated Aug 4, 2024

Buffer overflow in NetHack before 3.6.5 allows attackers to crash the process or execute code through an oversized SYMBOL option. The sym_val function passes the full configuration value to escapes for decoding into a fixed QBUFSZ stack buffer without first truncating the input. Exploitation requires a suid/sgid installation or a shared service that accepts attacker-supplied configuration files, with consequences ranging from a process crash to execution under the game process's privileges.

CVSS severity5.0
Medium
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in NetHack before 3.6.5 allows attackers to crash the process or execute code through an oversized SYMBOL option. The sym_val function passes the full configuration value to escapes for decoding into a fixed QBUFSZ stack buffer without first truncating the input. Exploitation requires a suid/sgid installation or a shared service that accepts attacker-supplied configuration files, with consequences ranging from a process crash to execution under the game process's privileges.

The record

CVE
CVE-2020-5213
Published
Jan 28, 2020
Updated
Aug 4, 2024
Vendor
NetHack
Product
NetHack
Classifications
CWE-120, T1068
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Jan 28, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.6.5

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

NetHack · NetHackversion=< 3.6.5

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.0GitHub, Inc.CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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