CVE-2026-33636Network attack vector

Process crash via NEON palette tail underflow

Published Mar 26, 2026 · Updated Mar 26, 2026

Out-of-bounds access in libpng 1.6.36 through 1.6.55 allows attackers to crash ARM/AArch64 processes via crafted paletted PNG files. Fixed-size NEON loops in arm/palette_neon_intrinsics.c process incomplete RGB or RGBA tail chunks, reading and writing before the row buffer. Reachability requires NEON-enabled ARM/AArch64 builds and palette expansion; confirmed impact is a process crash, while heap disclosure and corruption are plausible and code execution is not demonstrated.

CVSS severity7.6
High
EPSS probability0.74%
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 access in libpng 1.6.36 through 1.6.55 allows attackers to crash ARM/AArch64 processes via crafted paletted PNG files. Fixed-size NEON loops in arm/palette_neon_intrinsics.c process incomplete RGB or RGBA tail chunks, reading and writing before the row buffer. Reachability requires NEON-enabled ARM/AArch64 builds and palette expansion; confirmed impact is a process crash, while heap disclosure and corruption are plausible and code execution is not demonstrated.

The record

CVE
CVE-2026-33636
Published
Mar 26, 2026
Updated
Mar 26, 2026
Vendor
PNG Development Group
Product
libpng
Classifications
CWE-125, CWE-787, 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=>= 1.6.36, < 1.6.56

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PNG Development Group · libpngversion=>= 1.6.36, < 1.6.56

Published CVSS scores

7.6GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
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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