CVE-2020-13586Public exploit

Code execution via oversized SST record copy

Published Feb 4, 2021 · Updated Aug 4, 2024

Heap buffer overflow in SoftMaker Office PlanMaker 2021 Revision 1014 allows attackers to execute code via a malformed Excel file. The SST record parser allocates 0x6060 bytes, trusts the record's 16-bit length, and passes that length minus eight to memcpy without bounding it to the destination. Exploitation requires a user to open the crafted document; successful corruption runs code in the PlanMaker process, while the demonstrated failure mode is a crash.

CVSS severity7.8
High
EPSS probability1.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in SoftMaker Office PlanMaker 2021 Revision 1014 allows attackers to execute code via a malformed Excel file. The SST record parser allocates 0x6060 bytes, trusts the record's 16-bit length, and passes that length minus eight to memcpy without bounding it to the destination. Exploitation requires a user to open the crafted document; successful corruption runs code in the PlanMaker process, while the demonstrated failure mode is a crash.

The record

CVE
CVE-2020-13586
Published
Feb 4, 2021
Updated
Aug 4, 2024
Vendor
SoftMaker Software GmbH
Product
PlanMaker
Classifications
CWE-122, CWE-787, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 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 PlanMaker 2021 (Revision 1014)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

SoftMaker Software GmbH · PlanMakerversion=SoftMaker Software GmbH SoftMaker Office PlanMaker 2021 (Revision 1014)

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8Cisco TalosCVSS:3.0/AV:N/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 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 exploitPublished

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
T1204.002Malicious File
T1203Exploitation for Client Execution

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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