CVE-2021-21808Public exploitNetwork attack vector

Memory corruption via unchecked PNG palette write

Published Jun 11, 2021 · Updated Aug 3, 2024

Heap buffer overflow in Accusoft ImageGear 19.9 allows attackers to corrupt process memory by supplying a crafted PNG file. The png_palette_process function writes palette data without checking the destination buffer size, causing an out-of-bounds heap write during PNG loading. The condition requires an application using the SDK to process the malformed image and corrupts or terminates that host process.

CVSS severity8.1
High
EPSS probability1.00%
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 Accusoft ImageGear 19.9 allows attackers to corrupt process memory by supplying a crafted PNG file. The png_palette_process function writes palette data without checking the destination buffer size, causing an out-of-bounds heap write during PNG loading. The condition requires an application using the SDK to process the malformed image and corrupts or terminates that host process.

The record

CVE
CVE-2021-21808
Published
Jun 11, 2021
Updated
Aug 3, 2024
Vendor
Accusoft
Product
ImageGear
Classifications
CWE-120, CWE-119, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 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 19.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Accusoft · ImageGearversion=Accusoft ImageGear 19.9

Published CVSS scores

8.8NIST NVDCVSS:3.1/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
8.1Cisco TalosCVSS:3.0/AV:N/AC:H/PR:N/UI:N/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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
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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