CVE-2026-33636

7.6 HIGH 0.8% exploit odds Fix listed Memory safety Library

What it is

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit paletted rows to RGB or RGBA, the Neon loop processes a final partial chunk without verifying that enough input pixels remain. Because the implementation works backward from the end of the row, the final iteration dereferences pointers before the start of the row buffer (OOB read) and writes expanded pixel data to the same underflowed positions (OOB write). This is reachable via normal decoding of attacker-controlled PNG input if Neon is enabled. Version 1.6.56 fixes the issue.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of service disruption.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-03-26 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 10:37 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 7.6 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-03-26 17:16 UTC
Last modified: 2026-06-17 10:37 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Analyzed

Affected

Libpng < 1.6.56

Attack profile CVSS 3.1 · 7.6

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-33636.md and follow it. Check whether this project is affected by CVE-2026-33636. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record