CVE-2021-43257Public exploitNetwork attack vector

Code execution via unescaped exported CSV formulas

Published Apr 14, 2022 · Updated Aug 4, 2024

CSV injection in MantisBT before 2.25.3 allows remote authenticated users to execute spreadsheet formulas through exported issue data. The csv_escape_string() function fails to prefix cells beginning with =, -, +, or @, so Excel interprets attacker-controlled issue fields as formulas. Exploitation requires another user to export and open the CSV in Excel, where a formula can execute commands or expose information.

CVSS severity7.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSV injection in MantisBT before 2.25.3 allows remote authenticated users to execute spreadsheet formulas through exported issue data. The csv_escape_string() function fails to prefix cells beginning with =, -, +, or @, so Excel interprets attacker-controlled issue fields as formulas. Exploitation requires another user to export and open the CSV in Excel, where a formula can execute commands or expose information.

The record

CVE
CVE-2021-43257
Published
Apr 14, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1236, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2022CVE 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 vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.0NIST NVDAV:N/AC:M/Au:S/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1236Improper Neutralization of Formula Elements in a CSV File
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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