CVE-2021-29464

Heap overflow via unchecked JP2 box lengths

Published Apr 30, 2021 · Updated Aug 3, 2024

Heap-based buffer overflow in Exiv2 before 0.27.4 allows attackers to gain code execution via a crafted image during metadata writing. Jp2Image::encodeJp2Header() trusted JP2 box and sub-box lengths while copying data into a heap buffer without sufficient bounds checks. Exploitation requires a victim to run Exiv2 with a write operation such as insert; ordinary metadata reading does not trigger the flaw.

CVSS severity7.8
High
EPSS probability1.50%
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 gain code execution via a crafted image during metadata writing. Jp2Image::encodeJp2Header() trusted JP2 box and sub-box lengths while copying data into a heap buffer without sufficient bounds checks. Exploitation requires a victim to run Exiv2 with a write operation such as insert; ordinary metadata reading does not trigger the flaw.

The record

CVE
CVE-2021-29464
Published
Apr 30, 2021
Updated
Aug 3, 2024
Vendor
Exiv2
Product
Exiv2
Classifications
CWE-122, CWE-787, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 30, 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

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

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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