CVE-2026-33416Public exploitNetwork attack vector

Code execution via aliased-buffer use-after-free

Published Mar 26, 2026 · Updated Mar 26, 2026

Use-after-free in PNG Development Group libpng 1.2.1 through 1.6.55 allows remote attackers to corrupt heap memory via a crafted PNG. png_set_tRNS and png_set_PLTE share buffers between png_struct and png_info, so png_free_data leaves a dangling pointer that row transforms read or overwrite. Exploitation requires an application to free or replace palette or transparency data before continuing decoding; demonstrated code execution depends on predictable heap reuse, with PIE or ASLR requiring an additional information leak or brute force.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in PNG Development Group libpng 1.2.1 through 1.6.55 allows remote attackers to corrupt heap memory via a crafted PNG. png_set_tRNS and png_set_PLTE share buffers between png_struct and png_info, so png_free_data leaves a dangling pointer that row transforms read or overwrite. Exploitation requires an application to free or replace palette or transparency data before continuing decoding; demonstrated code execution depends on predictable heap reuse, with PIE or ASLR requiring an additional information leak or brute force.

The record

CVE
CVE-2026-33416
Published
Mar 26, 2026
Updated
Mar 26, 2026
Vendor
PNG Development Group
Product
libpng
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 2026Record 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=>= 1.2.1, < 1.6.56

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PNG Development Group · libpngversion=>= 1.2.1, < 1.6.56

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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-416Use After Free
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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