CVE-2021-29470Public exploit

Process crash via unchecked JP2 sub-box bounds

Published Apr 23, 2021 · Updated Aug 3, 2024

Out-of-bounds read in Exiv2 0.27.3 and earlier allows attackers to crash the process by writing metadata to a crafted JP2 file. Jp2Image::encodeJp2Header trusts the enclosing box length and reads a sub-box header without first verifying that a complete header remains. Exploitation requires a victim to invoke a metadata-writing action such as insert on the crafted file; ordinary metadata reads do not trigger the flaw.

CVSS severity4.7
Medium
EPSS probability1.57%
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 read in Exiv2 0.27.3 and earlier allows attackers to crash the process by writing metadata to a crafted JP2 file. Jp2Image::encodeJp2Header trusts the enclosing box length and reads a sub-box header without first verifying that a complete header remains. Exploitation requires a victim to invoke a metadata-writing action such as insert on the crafted file; ordinary metadata reads do not trigger the flaw.

The record

CVE
CVE-2021-29470
Published
Apr 23, 2021
Updated
Aug 3, 2024
Vendor
Exiv2
Product
Exiv2
Classifications
CWE-125, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 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=<= 0.27.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Exiv2 · Exiv2version=<= 0.27.3

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.7GitHub, Inc.CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
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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