CVE-2021-21949Public exploitNetwork attack vector

Code execution via unchecked JPEG table indexes

Published Apr 14, 2022 · Updated Apr 15, 2025

Out-of-bounds write in Accusoft ImageGear 19.10 allows attackers to execute code by supplying a crafted JPEG-JFIF file. The progressive JPEG parser uses unchecked four-bit AC and DC table identifiers, allowing negative offsets to bypass maximum-only signed bounds checks and overwrite a stack buffer. The host application must process the file; exploitation can crash its process or execute code in the process's security context.

CVSS severity8.8
High
EPSS probability1.10%
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 19.10 allows attackers to execute code by supplying a crafted JPEG-JFIF file. The progressive JPEG parser uses unchecked four-bit AC and DC table identifiers, allowing negative offsets to bypass maximum-only signed bounds checks and overwrite a stack buffer. The host application must process the file; exploitation can crash its process or execute code in the process's security context.

The record

CVE
CVE-2021-21949
Published
Apr 14, 2022
Updated
Apr 15, 2025
Vendor
Accusoft
Product
ImageGear
Classifications
CWE-129, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record 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=19.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Accusoft · ImageGearversion=19.10

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
9.8Cisco TalosCVSS:3.0/AV:N/AC:L/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-129Improper Validation of Array Index
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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