CVE-2021-27799Public exploitNetwork attack vector

Application crash via unchecked EAN length

Published Feb 26, 2021 · Updated Aug 3, 2024

Stack-based buffer overflow in Zint Barcode Generator 2.9.1 allows attackers to crash applications via crafted EAN input. The ean_leading_zeroes function in backend/upcean.c appends leading-zero data with strcat into a fixed-size stack buffer without enforcing the destination length, overrunning local_source during C API encoding. Exploitation requires an application that includes the library and accepts attacker-controlled EAN data; the documented consequence is process interruption, while arbitrary code execution is reported by the Arch Linux advisory.

CVSS severity7.5
High
EPSS probability2.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Zint Barcode Generator 2.9.1 allows attackers to crash applications via crafted EAN input. The ean_leading_zeroes function in backend/upcean.c appends leading-zero data with strcat into a fixed-size stack buffer without enforcing the destination length, overrunning local_source during C API encoding. Exploitation requires an application that includes the library and accepts attacker-controlled EAN data; the documented consequence is process interruption, while arbitrary code execution is reported by the Arch Linux advisory.

The record

CVE
CVE-2021-27799
Published
Feb 26, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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