CVE-2021-21235Network attack vector

Service interruption via infinite PNG parsing loop

Published Jan 6, 2021 · Updated Aug 3, 2024

Kamadak exif-rs 0.5.2 contains an uncontrolled loop that lets remote attackers interrupt service by supplying a crafted PNG to the parser. Reader::read_from_container fails to advance to an exit condition while processing crafted PNG container data, causing the calling process to loop indefinitely. Exploitation requires a reachable application to pass attacker-controlled PNG data to this function; affected behavior is limited to availability impact and applications that never pass PNG signatures are not affected.

CVSS severity6.5
Medium
EPSS probability1.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Kamadak exif-rs 0.5.2 contains an uncontrolled loop that lets remote attackers interrupt service by supplying a crafted PNG to the parser. Reader::read_from_container fails to advance to an exit condition while processing crafted PNG container data, causing the calling process to loop indefinitely. Exploitation requires a reachable application to pass attacker-controlled PNG data to this function; affected behavior is limited to availability impact and applications that never pass PNG signatures are not affected.

The record

CVE
CVE-2021-21235
Published
Jan 6, 2021
Updated
Aug 3, 2024
Vendor
Kamadak
Product
exif-rs
Classifications
CWE-400, CWE-835, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 6, 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== 0.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Kamadak · exif-rsversion== 0.5.2

Published CVSS scores

6.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/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.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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