CVE-2020-27819Public exploit

Service crash via NULL cell-string dereference

Published Feb 23, 2021 · Updated Aug 4, 2024

NULL pointer dereference in xls2csv before 1.6.2 allows context-dependent attackers to crash the process with a crafted XLS file. At src/xls2csv.c line 199, formula-cell handling passes a NULL cell->str value to strcmp without first checking the pointer. Exploitation requires the crafted file to be processed by xls2csv and terminates that converter process, with no reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in xls2csv before 1.6.2 allows context-dependent attackers to crash the process with a crafted XLS file. At src/xls2csv.c line 199, formula-cell handling passes a NULL cell->str value to strcmp without first checking the pointer. Exploitation requires the crafted file to be processed by xls2csv and terminates that converter process, with no reported data disclosure or modification.

The record

CVE
CVE-2020-27819
Published
Feb 23, 2021
Updated
Aug 4, 2024
Vendor
Libxls Project
Product
libxls
Classifications
CWE-476, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 23, 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=libxls before 1.6.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Libxls Project · libxlsversion=libxls before 1.6.2

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/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.

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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-476NULL Pointer Dereference
T1204.002User Execution: Malicious 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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