CVE-2026-42169: GIMP Heap Buffer Overflows in APNG and DDS
TL;DR - GIMP is affected by heap buffer overflow flaws in APNG and DDS image handling. - Risk is triggered when a user opens a malicious image file. - Patch details are not yet publicly confirmed in retrieved sources, so treat this as high priority.
Vulnerability at a Glance
| Field | Value |
|---|---|
| CVE ID | CVE-2026-42169 |
| CVSS score | 7.3 |
| Attack vector | Malicious file opened locally by a user; exact CVSS vector not provided in retrieved NVD data |
| Privileges required / auth required | No authentication to the target application is described; user interaction is implied because a crafted image must be opened |
| Patch available | Unknown from retrieved sources |
CVE-2026-42169 covers two memory corruption issues in GIMP’s image parsing path. According to the NVD description, one flaw exists in the APNG loader and another in the DDS plug-in. Both can be triggered by opening a specially crafted image file, and both may lead to code execution.
For defenders, the practical meaning is straightforward: this is not a wormable network service bug, but it is still serious anywhere users routinely open untrusted design assets, images from email, files from chat platforms, or downloads from the web. Creative teams, marketing staff, and support teams that inspect customer-submitted media are the most exposed.
What Is This Vulnerability?
The technical root cause described publicly is a pair of heap-based buffer overflows in different GIMP image handlers. In the APNG path, the flaw occurs when the frame control chunk width, fcTL, exceeds the PNG header width, IHDR. That mismatch leads to pixel data being written past the end of an allocated heap buffer. In plain terms, the parser appears to trust size-related metadata from the file in a way that allows memory writes outside intended bounds.
The second issue affects the DDS plug-in. The NVD description says it is caused by a BPP mismatch in the load_layer() function. BPP here refers to bits per pixel. A mismatch of expected versus actual pixel format can easily produce incorrect allocation sizing, row-stride calculations, or copy lengths. When that happens in native code, the result is often an out-of-bounds write or read. In this CVE, the issue is specifically described as a heap-based buffer overflow, which means the bug can corrupt heap memory during image processing.
These are classic malicious-file parsing conditions. The attacker does not need shell access or credentials to the target host. Instead, they need a delivery path for a crafted image and a user who opens it with a vulnerable GIMP build. That makes the vulnerability relevant for desktop security, VDI fleets, build systems that process images, and content-handling workflows.
Technical Notes
The most specific publicly verified root-cause details currently available are:
- APNG loader heap-buffer-overflow when
fcTLwidth exceedsIHDRwidth - Bugzilla title points to
file-png.c - DDS plug-in heap overflow due to BPP mismatch in
load_layer()
Illustrative validation logic that would prevent this class of bug typically looks like:
if (fctl_width > ihdr_width) {
return PARSE_ERROR_INVALID_DIMENSIONS;
}
if (calculated_bpp != declared_bpp) {
return PARSE_ERROR_UNSUPPORTED_PIXEL_FORMAT;
}
That sample is conceptual only, not confirmed upstream code. The defensive takeaway is to look for image parsers that fail to enforce strict consistency between header fields, frame metadata, and allocation sizes.
Who Is Affected?
The confirmed affected product is GIMP, the GNU Image Manipulation Program. The retrieved sources explicitly identify GIMP and describe vulnerabilities in its APNG loader and DDS plug-in. The Red Hat Bugzilla title also ties the APNG issue to GIMP and file-png.c, which strengthens confidence in the product mapping.
What is not publicly confirmed in the retrieved material is the exact affected version range. The NVD output available for this task did not include specific vulnerable versions, and the referenced Red Hat pages did not expose a fixed upstream release or a bounded affected range in the available snippets. Because of that, it would be inaccurate to claim a version window such as “X through Y” or a fixed version number. At this time, the only defensible statement is that GIMP is affected, while exact affected versions remain undisclosed in the sources used here.
That uncertainty matters operationally. If you run GIMP anywhere in the enterprise, especially on endpoints that open untrusted image files, you should assume your installed version may be affected until you verify package advisories from your operating system vendor, upstream release notes, or a confirmed downstream backport notice. For Linux environments, distribution package names may differ from upstream release numbering, so check both the application version and distro security advisories.
Technical Notes
You can inventory GIMP installations with standard package queries:
# Debian/Ubuntu
dpkg -l | grep -i '^ii' | grep -i gimp
# RHEL, CentOS Stream, Fedora
rpm -qa | grep -i '^gimp'
# Arch Linux
pacman -Qs gimp
# Flatpak
flatpak list | grep -i gimp
You can also confirm the runtime version on a host:
gimp --version
If you do not yet have a vendor advisory mapping package builds to this CVE, document all installed versions and treat them as potentially exposed pending confirmation.
CVSS Score Breakdown
The published CVSS base score is 7.3, which places this issue in the high-severity range. The full vector string was not present in the retrieved NVD tool output, so it is important not to invent individual metric values such as Attack Complexity, Privileges Required, or User Interaction. Still, the narrative description gives enough context to explain why the score is materially significant.
First, the vulnerability can potentially lead to code execution. Native memory corruption in a desktop application that handles attacker-controlled files often receives a comparatively high score because exploitation may result in arbitrary code running with the privileges of the user who launched the application. Second, the trigger condition appears to be low-friction in the sense that a crafted file is the primary requirement. If the file reaches a user and is opened, the vulnerable parsing path may execute automatically.
At the same time, the attack does appear to require user interaction, because the current description says the issue is triggered by opening a specially crafted image file. That usually reduces exposure relative to remotely reachable daemon bugs, but it does not make the issue low risk. In many organizations, users regularly open external media assets, screenshots, logos, and customer-submitted files. In those workflows, “user-assisted” can still translate into realistic exploitability.
When the full vector is unavailable, defenders should avoid over-precision. Use the known facts: high severity, likely malicious-file attack path, possible code execution, and no confirmed in-the-wild exploitation yet. That is sufficient to justify near-term remediation, file-handling controls, and user awareness measures.
Exploitation Status
Based on the retrieved data, exploitation in the wild is not confirmed. The CVE is not listed in CISA’s Known Exploited Vulnerabilities catalog at the time of lookup, which means there is no CISA-backed confirmation of active exploitation. That does not prove attackers are not testing it, but it does mean public authoritative evidence of in-the-wild abuse is absent from the sources reviewed here.
Likewise, no verified public proof-of-concept was identified in the retrieved material. The available references point to the NVD record, a Red Hat CVE page, and a Red Hat Bugzilla issue. Those sources confirm the bug class and technical conditions, but they do not provide a public exploit repository, sample malicious file, or a demonstrated exploit chain.
The correct practitioner summary is therefore:
- Public PoC: none verified in retrieved sources
- Active exploitation: not confirmed
- CISA KEV: not listed at time of writing
In the absence of confirmed exploitation data, defenders should assume opportunistic weaponization is possible because malicious-file parser bugs often attract fuzzing, exploit research, and copycat proof-of-concept development soon after disclosure. If your environment handles untrusted image content, it is prudent to prioritize mitigations even before a public PoC appears.
How to Detect It
Detection for this CVE is mostly about identifying risky behavior and suspicious crash telemetry rather than matching a mature network signature. The vulnerable paths are triggered when GIMP opens crafted APNG or DDS files, so endpoint telemetry, crash logs, and process execution context are your best signals. If you collect desktop EDR data, focus on GIMP opening files from email attachment directories, browser download folders, temporary collaboration-sync paths, and shared customer-upload repositories.
You should also watch for application crashes or memory-protection terminations involving GIMP shortly after opening .png, .apng, or .dds files. On Linux desktops, this may show up in journalctl, desktop crash handlers, kernel logs, or EDR process telemetry. A crash alone does not prove exploitation, but a sequence of downloaded image -> GIMP launch -> abnormal termination is a useful triage lead.
Technical Notes
Example Linux log hunting:
# System journal for GIMP crashes or segfaults
journalctl --since "2026-08-01" | grep -Ei 'gimp|segfault|abrt|core dumped'
# Kernel messages that may show userspace crashes
dmesg | grep -Ei 'gimp|segfault'
Example patterns to look for:
gimp[PID]: segfault at ...
gimp[PID]: malloc(): corrupted top size
kernel: traps: gimp[PID] general protection fault ...
abrt-server: Executable '/usr/bin/gimp' crashed
Basic Sigma-style detection idea for suspicious file-open context:
title: GIMP Opening Untrusted Downloaded Image Followed by Crash
logsource:
category: process_creation
detection:
sel_proc:
Image|endswith: '/gimp'
sel_args:
CommandLine|contains:
- '.png'
- '.apng'
- '.dds'
condition: sel_proc and sel_args
level: medium
Example EDR or SIEM query logic to adapt:
process_name = "gimp"
AND (
command_line CONTAINS ".png" OR
command_line CONTAINS ".apng" OR
command_line CONTAINS ".dds"
)
AND (
parent_path CONTAINS "/Downloads/" OR
file_path CONTAINS "/tmp/" OR
file_path CONTAINS "/var/tmp/" OR
file_path CONTAINS "Attachments"
)
Because there is no confirmed network exploit path in the retrieved sources, network IDS signatures are less reliable than endpoint observation. If you operate secure file-handling pipelines, sandbox APNG and DDS files before analysts or designers open them.
Mitigation and Patching
The preferred mitigation is to upgrade to a vendor-confirmed fixed version as soon as one is published for your platform. However, the exact fixed version number is not disclosed in the retrieved sources available for this article. For that reason, it would be incorrect to claim a specific version such as “upgrade to X.Y.Z.” Instead, defenders should consult upstream GIMP release notes and their Linux distribution or packaging channel advisories for the package build that explicitly references CVE-2026-42169.
Until a confirmed fixed version is identified, reduce exposure operationally. The strongest temporary control is to avoid opening untrusted APNG and DDS files with GIMP, especially on systems used for internet-sourced media triage. If your workflow permits, use isolated VMs or sandboxed containers for initial inspection of third-party images. Organizations with content-handling teams should notify users that opening externally sourced image files in vulnerable desktop apps can be enough to trigger exploitation.
If you package GIMP centrally, consider temporarily restricting APNG and DDS handling in high-risk environments or removing GIMP from systems that do not strictly need it until patched builds are available. This is particularly sensible for kiosks, shared workstations, and endpoints used by non-technical staff.
Technical Notes
Package update commands to use once your vendor publishes a fixed build:
# Debian/Ubuntu
sudo apt update && sudo apt install --only-upgrade gimp
# RHEL / Rocky / Alma / Fedora
sudo dnf upgrade gimp
# openSUSE
sudo zypper update gimp
# Arch Linux
sudo pacman -Syu gimp
# Flatpak
flatpak update org.gimp.GIMP
Temporary workaround options, depending on your environment:
# Example: remove GIMP from systems that do not require it
sudo apt remove gimp
sudo dnf remove gimp
# Example: quarantine risky file types at mail or upload gateways
# Block or hold for review:
# *.apng
# *.dds
If you need a policy control, communicate this clearly: do not open .apng or .dds files from untrusted sources in GIMP until a vendor advisory confirms the installed package includes a fix for CVE-2026-42169.
References
The primary public reference for this CVE is the NVD record, which identifies the issue as a heap-buffer-overflow vulnerability in GIMP’s APNG loader and a heap-based overflow in the DDS plug-in. The NVD description is the authoritative source for the currently verified technical summary used in this article.
The Red Hat CVE page and associated Bugzilla entry provide additional context, especially the Bugzilla title, which specifies that the APNG issue occurs when fcTL width exceeds IHDR width and points to file-png.c. At the time of writing, the retrieved material from these references does not disclose an exact affected version range or fixed version number, so defenders should verify those details directly from updated advisories before closing remediation tickets.
- NVD CVE entry for CVE-2026-42169
- Red Hat CVE page: https://access.redhat.com/security/cve/CVE-2026-42169
- Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2461725
- GIMP project site: https://www.gimp.org
For further reading on related vulnerabilities, check out our articles on CVE-2026-10158 and what is insecure direct object reference.
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