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Fencer Vulns
high 7.8

CVE-2021-30184 json

GNU Chess 6.2.7 allows attackers to execute arbitrary code via crafted PGN (Portable Game Notation) data.

published 2021-04-07 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-17117

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

GNU Chess 6.2.7 allows attackers to execute arbitrary code via crafted PGN (Portable Game Notation) data. This is related to a buffer overflow in the use of a .tmp.epd temporary file in the cmd_pgnload and cmd_pgnreplay functions in frontend/cmd.cc.

Patch / fix

  • gnuchess Debian 12 6.2.7-1+deb12u1
  • gnuchess Debian 14, Debian 13 6.2.9-0.1

debian advisories DEBIAN-CVE-2021-30184

  • gnuchess Ubuntu 22.04 LTS 6.2.7-1+deb11u1build0.22.04.1
  • gnuchess Ubuntu 24.04 LTS 6.2.7-1+deb11u1build0.24.04.1

ubuntu advisories UBUNTU-CVE-2021-30184

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • gnuchess openSUSE Tumbleweed 6.2.9-1.2

opensuse advisories openSUSE-SU-2024:10799-1

  • gnuchess Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 6.2.9-r0

alpine advisories ALPINE-CVE-2021-30184

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-30184 updated cvss 7.8

gnuchess: buffer overflows in the cmd_pgnload() and cmd_pgnreplay() functions in frontend/cmd.cc

  • Red Hat Enterprise Linux 6 gnuchess
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.77% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • lists.gnu.org https://lists.gnu.org/archive/html/bug-gnu-chess/2021-04/msg00000.html referenced PoC, tagged "exploit" by a source, unverified
  • lists.gnu.org https://lists.gnu.org/archive/html/bug-gnu-chess/2021-04/msg00001.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.