CVE-2020-21684Public exploit

Converter crash via negative font-table index

Published Aug 10, 2021 · Updated Aug 4, 2024

Global buffer overflow in fig2dev 3.2.7b allows local users to crash the converter by processing a crafted Xfig file as pict2e output. In genpict2e.c, put_font uses a negative font selector to access the global texfonts table without a lower-bound check, causing an out-of-bounds read. Exploitation requires a user or automated workflow to convert the crafted file; the demonstrated consequence is process termination, not data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Global buffer overflow in fig2dev 3.2.7b allows local users to crash the converter by processing a crafted Xfig file as pict2e output. In genpict2e.c, put_font uses a negative font selector to access the global texfonts table without a lower-bound check, causing an out-of-bounds read. Exploitation requires a user or automated workflow to convert the crafted file; the demonstrated consequence is process termination, not data disclosure or modification.

The record

CVE
CVE-2020-21684
Published
Aug 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2021CVE 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?

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

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1204.002Malicious File

Public exploit references

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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