CVE-2020-13544

Heap memory corruption via sign-extended record length

Published Jan 6, 2021 · Updated Aug 4, 2024

Sign extension in TextMaker 2021 revision 1014 allows attackers to corrupt heap memory by enticing a user to open a crafted document. The document-record 0x001f parser treats an unsigned 16-bit record length as a signed loop index, which wraps negative and directs file bytes outside the allocated heap buffer. User interaction is required, and the resulting attacker-controlled byte writes corrupt process memory beyond the intended allocation.

CVSS severity8.8
High
EPSS probability1.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sign extension in TextMaker 2021 revision 1014 allows attackers to corrupt heap memory by enticing a user to open a crafted document. The document-record 0x001f parser treats an unsigned 16-bit record length as a signed loop index, which wraps negative and directs file bytes outside the allocated heap buffer. User interaction is required, and the resulting attacker-controlled byte writes corrupt process memory beyond the intended allocation.

The record

CVE
CVE-2020-13544
Published
Jan 6, 2021
Updated
Aug 4, 2024
Vendor
SoftMaker Software GmbH
Product
TextMaker
Classifications
CWE-681, CWE-194, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 6, 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?

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

  1. Affected versionversion=SoftMaker Software GmbH SoftMaker Office TextMaker 2021 (revision 1014)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

SoftMaker Software GmbH · TextMakerversion=SoftMaker Software GmbH SoftMaker Office TextMaker 2021 (revision 1014)

Published CVSS scores

8.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-681Incorrect Conversion between Numeric Types
CWE-194Unexpected Sign Extension
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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