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NVD / CVE Program· CNA GitHub_M

CVE-2026-33636: LIBPNG has ARM NEON Palette Expansion Out-of-Bounds Read on AArch64

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.75% (FIRST EPSS); higher than 55% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: azl3 libpng 1.6.55-1 on Azure Linux 3.0 1.6.56-1; cbl2 libpng 1.6.55-1 on CBL Mariner 2.0 1.6.56-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to azl3 libpng 1.6.55-1 on Azure Linux 3.0 1.6.56-1; cbl2 libpng 1.6.55-1 on CBL Mariner 2.0 1.6.56-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.6 · v3.1—No exploit Fix available
Published
Mar 26, 2026
Updated
Jun 17, 2026
EPSS
0.7% · 55th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.6
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
libpnglibpng

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • libpng libpng1.6.36 and later · before 1.6.56

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • pnggroup libpng

    • >= 1.6.36, < 1.6.56affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10firefoxbefore 140.9.1-1.el10_1140.9.1-1.el10_1
AlmaLinux:10java-21-openjdkbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-demobefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-demo-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-demo-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-develbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-devel-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-devel-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-headlessbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-headless-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-headless-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-javadocbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-javadoc-zipbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-jmodsbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-jmods-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-jmods-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-srcbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-src-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-src-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-static-libsbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-static-libs-fastdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1
AlmaLinux:10java-21-openjdk-static-libs-slowdebugbefore 1:21.0.11.0.10-2.el10_2.alma.11:21.0.11.0.10-2.el10_2.alma.1

+96

Same product

libpng: all records

Other highest-scoring records for the same primary product.

  • CVE-2010-1205Buffer overflow in pngpread.c in libpng before 1.2.44 and 1.4.x before 1.4.3, as used in progressive applications, might allow remote attack
    52Plan
  • CVE-2017-12652libpng before 1.6.32 does not properly check the length of chunks against the user limit.
    40Plan
  • CVE-2015-8540Integer underflow in the png_check_keyword function in pngwutil.c in libpng 0.90 through 0.99, 1.0.x before 1.0.66, 1.1.x and 1.2.x before 1
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-25646Feb 10, 2026 · LIBPNG has a heap buffer overflow in png_set_quantize
    33Monitor
  • ← EarlierCVE-2026-33416Mar 26, 2026 · LIBPNG has use-after-free via pointer aliasing in `png_set_tRNS` and `png_set_PLTE`
    30Monitor
  • Later →CVE-2026-34757Apr 9, 2026 · LIBPNG has a yse-after-free in png_set_PLTE, png_set_tRNS and png_set_hIST leading to corrupted chunk data and potential heap information disclosure
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 libpng 1.6.55-1 on Azure Linux 3.01.6.56-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 libpng 1.6.55-1 on CBL Mariner 2.01.6.56-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:firefox140.9.1-1.el9_7.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:firefox-x11140.9.1-1.el9_7.alma.1 · AlmaLinux:9Package registry (OSV)
almalinux:java-1.8.0-openjdk1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-accessibility1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-accessibility-fastdebug1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-accessibility-slowdebug1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-demo1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-demo-fastdebug1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-1.8.0-openjdk-demo-slowdebug1:1.8.0.492.b09-1.el8 · AlmaLinux:8Package registry (OSV)
almalinux:java-25-openjdk1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-crypto-adapter1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-crypto-adapter-fastdebug1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-crypto-adapter-slowdebug1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-demo1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-demo-fastdebug1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:java-25-openjdk-demo-slowdebug1:25.0.3.0.9-1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:libpng2:1.6.40-8.el10_1.3 · AlmaLinux:10Package registry (OSV)
almalinux:libpng-devel2:1.6.40-8.el10_1.3 · AlmaLinux:10Package registry (OSV)
almalinux:thunderbird140.9.1-1.el9_7.alma.1 · AlmaLinux:9Package registry (OSV)
alpine:libpng1.6.56-r0 · Alpine:v3.20Package registry (OSV)
debian:libpng1.61.6.39-2+deb12u4 · Debian:12Package registry (OSV)
opensuse:libpng161.6.40-150600.3.17.1 · openSUSE:Leap 15.6Package registry (OSV)
red hat:firefox0:140.9.1-1.el8_2 · Red Hat:rhel_aus:8.2::appstreamPackage registry (OSV)
red hat:firefox-debuginfo0:140.9.1-1.el8_2 · Red Hat:rhel_aus:8.2::appstreamPackage registry (OSV)
red hat:firefox-debugsource0:140.9.1-1.el8_2 · Red Hat:rhel_aus:8.2::appstreamPackage registry (OSV)
red hat:firefox-x110:140.9.1-1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:libpng2:1.6.40-8.el10_1.3 · Red Hat:enterprise_linux:10.1Package registry (OSV)
red hat:libpng-debuginfo2:1.6.40-8.el10_1.3 · Red Hat:enterprise_linux:10.1Package registry (OSV)

+11

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-2280173 days apartLIBPNG has an integer truncation causing heap buffer over-read in png_image_write_*
    31Monitor
  • CVE-2026-2269573 days apartLIBPNG has a heap buffer over-read in png_image_read_direct_scaled (regression from CVE-2025-65018 fix)
    28Monitor
  • CVE-2025-66293113 days apartLIBPNG has an out-of-bounds read in png_image_read_composite
    28Monitor
  • CVE-2025-64720121 days apartLIBPNG is vulnerable to a buffer overflow in `png_image_read_composite` via incorrect palette premultiplication
    28Monitor
  • CVE-2025-64505121 days apartLIBPNG is vulnerable to a heap buffer overflow in `png_do_quantize` via malformed palette index
    24Monitor
  • CVE-2025-64506121 days apartLIBPNG is vulnerable to a heap buffer over-read in `png_write_image_8bit` with grayscale+alpha or RGB/RGBA images
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records