CVE-2021-29457Public exploit

Code execution via undersized JP2 box write

Published Apr 19, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in Exiv2 before 0.27.4 allows attackers to execute code when a crafted image is processed for metadata writing. Jp2Image::doWriteMetadata trusts a JP2 box length below eight bytes and writes an eight-byte box header beyond the allocated heap buffer. Exploitation requires a victim to invoke a metadata-writing action, such as insert, on the crafted image; ordinary metadata reads do not trigger the flaw.

CVSS severity7.8
High
EPSS probability2.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Exiv2 before 0.27.4 allows attackers to execute code when a crafted image is processed for metadata writing. Jp2Image::doWriteMetadata trusts a JP2 box length below eight bytes and writes an eight-byte box header beyond the allocated heap buffer. Exploitation requires a victim to invoke a metadata-writing action, such as insert, on the crafted image; ordinary metadata reads do not trigger the flaw.

The record

CVE
CVE-2021-29457
Published
Apr 19, 2021
Updated
Aug 3, 2024
Vendor
Exiv2
Product
Exiv2
Classifications
CWE-122, T1204.002, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 19, 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=< 0.27.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Exiv2 · Exiv2version=< 0.27.4

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
0.0GitHubCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:N

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-122Heap-based Buffer Overflow
T1204.002User Execution: Malicious File
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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