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

high Tenable Cloud Security Plugin ID 462708

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 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE`
 each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across
 two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng
 1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS`
 sets `png_ptr->trans_alpha = info_ptr->trans_alpha` (256-byte buffer) and `png_set_PLTE` sets
 `info_ptr->palette = png_ptr->palette` (768-byte buffer). In both cases, calling `png_free_data` (with
 `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr`
 pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to
 the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both
 functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes
 the issue. (CVE-2026-33416)

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-2026-33416

Plugin Details

Severity: High

ID: 462708

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/2/2026

Risk Information

VPR

Risk Factor: High

Score: 7.9

Percentile: 99.35

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 6

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

CVSS Score Source: CVE-2026-33416

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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

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

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/27/2026

Vulnerability Publication Date: 3/10/2026

Reference Information

CVE: CVE-2026-33416