CVE-2026-34757: LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network

Routine

MEDIUM 5.1WATCHLISTUPGRADEMITIGATE

CVE-2026-34757 is a medium-severity flaw (CVSS 5.1) affecting libpng, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the replacement buffer. The setter frees the internal buffer b

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.1 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 91%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-04-09
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: debian · libpng

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-09 15:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

libpng libpng UPGRADE

Affected: >= 1.0.9 and < 1.6.57

Fixed in: 1.6.57

Safe to downgrade to: a release before 1.0.9

1. Check installed version

apt-cache policy libpng || rpm -q libpng || libpng --version

2. UPGRADE to 1.6.57 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libpng

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libpng

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.0.9 (Debian / Ubuntu)

apt-cache madison libpng sudo apt install libpng=<VERSION_BEFORE_1.0.9> sudo apt-mark hold libpng

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libpng sudo dnf downgrade libpng-<VERSION_BEFORE_1.0.9> sudo dnf versionlock add libpng

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34757?

libpng: upgrade to 1.6.57; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-34757 being exploited?

CVE-2026-34757 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34757 affect?

CVE-2026-34757 affects libpng, debian linux. Severity is medium (CVSS 5.1). LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from png_get_PLTE, png_get_tRNS, or png_get_

How urgent is CVE-2026-34757?

Priority 30/100. Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities · libpng vulnerabilities

References

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