CVE-2021-21776Public exploitNetwork attack vector

Memory corruption via unchecked SGI copy length

Published Mar 31, 2021 · Updated Aug 3, 2024

Out-of-bounds write in Accusoft ImageGear 19.8 allows context-dependent attackers to corrupt memory via a malformed SGI file. The SGI decoder allocates a buffer as twice the header xsize plus one, then copies a file-controlled byte count into it without checking the destination bound. A host application must process the file; the resulting heap corruption can crash the process or enable code execution.

CVSS severity8.8
High
EPSS probability1.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Accusoft ImageGear 19.8 allows context-dependent attackers to corrupt memory via a malformed SGI file. The SGI decoder allocates a buffer as twice the header xsize plus one, then copies a file-controlled byte count into it without checking the destination bound. A host application must process the file; the resulting heap corruption can crash the process or enable code execution.

The record

CVE
CVE-2021-21776
Published
Mar 31, 2021
Updated
Aug 3, 2024
Vendor
Accusoft
Product
ImageGear
Classifications
CWE-131, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 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?

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

  1. Affected versionversion=Accusoft ImageGear Accusoft ImageGear 19.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Accusoft · ImageGearversion=Accusoft ImageGear Accusoft ImageGear 19.8

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
9.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
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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