Detections
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Echo: libpng1.6: security update to 1.6.56-1

high Tenable Cloud Security Plugin ID 464434

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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. (CVE-2026-33636)

Solution

Update the libpng1.6 library and its related packages to version 1.6.56-1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-33636

Plugin Details

Severity: High

ID: 464434

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

Percentile: 96.23

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 6.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:C

CVSS Score Source: CVE-2026-33636

CVSS v3

Risk Factor: High

Base Score: 7.6

Temporal Score: 6.6

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 3/27/2026

Vulnerability Publication Date: 3/26/2026

Reference Information

CVE: CVE-2026-33636