CVE-2021-40241Public exploit

Process-memory corruption via unbounded LANG formatting

Published Oct 31, 2022 · Updated May 7, 2025

Buffer overflow in xfig 3.2.7 allows local users to corrupt process memory by launching it with an excessively long LANG value. In src/w_help.c, the help-viewer path builder passes the unbounded LANG environment string to sprintf() for a fixed-size filename buffer. The user must control the process environment and start xfig; upstream reports no automatic invocation or cross-user exposure.

CVSS severity9.8
Critical
EPSS probability1.02%
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 xfig 3.2.7 allows local users to corrupt process memory by launching it with an excessively long LANG value. In src/w_help.c, the help-viewer path builder passes the unbounded LANG environment string to sprintf() for a fixed-size filename buffer. The user must control the process environment and start xfig; upstream reports no automatic invocation or cross-user exposure.

The record

CVE
CVE-2021-40241
Published
Oct 31, 2022
Updated
May 7, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 31, 2022CVE publishedPublication date reported by the CVE source.
  2. May 7, 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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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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