CVE-2021-30184

Arbitrary code execution via PGN buffer overflow

Published Apr 7, 2021 · Updated Jan 12, 2025

GNU Chess 6.2.7 buffer overflow allows attackers to execute arbitrary code via crafted Portable Game Notation (PGN) data. The cmd_pgnload and cmd_pgnreplay functions in frontend/cmd.cc use a .tmp.epd temporary file without bounding copied input, allowing crafted game records to overwrite memory. Exploitation requires a local user to open or replay attacker-supplied PGN content, after which process-level code execution can compromise confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability1.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

GNU Chess 6.2.7 buffer overflow allows attackers to execute arbitrary code via crafted Portable Game Notation (PGN) data. The cmd_pgnload and cmd_pgnreplay functions in frontend/cmd.cc use a .tmp.epd temporary file without bounding copied input, allowing crafted game records to overwrite memory. Exploitation requires a local user to open or replay attacker-supplied PGN content, after which process-level code execution can compromise confidentiality, integrity, and availability.

The record

CVE
CVE-2021-30184
Published
Apr 7, 2021
Updated
Jan 12, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Jan 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1203Exploitation for Client Execution

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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