CVE-2025-50952 Overview
CVE-2025-50952 is a NULL pointer dereference vulnerability [CWE-476] in OpenJPEG version 2.5.0. The flaw resides in the discrete wavelet transform component located at /openjp2/dwt.c. OpenJPEG is an open-source JPEG 2000 codec maintained by UCLouvain and is widely embedded in image processing libraries, document viewers, and multimedia frameworks.
An attacker who supplies a crafted JPEG 2000 file to a vulnerable application can trigger the dereference and cause the process to crash. The vulnerability is network-reachable when applications process untrusted images from remote sources.
Critical Impact
Processing a malicious JPEG 2000 file causes a NULL pointer dereference in the wavelet transform routine, terminating the host application and producing a denial-of-service condition.
Affected Products
- UCLouvain OpenJPEG 2.5.0
- Applications and libraries that bundle or link against the affected OpenJPEG version
- Linux distributions shipping the vulnerable package, including Debian LTS
Discovery Timeline
- 2025-08-07 - CVE-2025-50952 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-50952
Vulnerability Analysis
The defect is a NULL pointer dereference within the discrete wavelet transform (DWT) implementation in src/lib/openjp2/dwt.c. During decoding of a JPEG 2000 codestream, OpenJPEG performs inverse wavelet transforms on tile components. When specific header fields or tile parameters describe an inconsistent or malformed image structure, a pointer used by the DWT routine is not initialized before use.
Dereferencing that pointer forces the process to read from address 0x0, which the operating system rejects with a segmentation fault. The result is an unhandled crash of any application that invokes the decoder on attacker-controlled input. Confidentiality and integrity impact are limited, but availability of the consuming process is lost.
Root Cause
The root cause is missing validation of internal state before pointer access in the DWT decoding path. OpenJPEG accepts a malformed codestream that produces a code path in which an object pointer is left NULL. The function then invokes an operation on that pointer without a guard, matching the pattern described by CWE-476: NULL Pointer Dereference.
Attack Vector
Exploitation requires only that a vulnerable process decode a malicious JPEG 2000 file. Delivery paths include email attachments, web uploads, document conversion pipelines, thumbnail generators, and any server-side image processing service. No authentication or user interaction beyond opening the file is required. Refer to the GitHub Issue Discussion for reproducer details.
No public exploit code is available in Exploit-DB, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.
Detection Methods for CVE-2025-50952
Indicators of Compromise
- Repeated segmentation faults or SIGSEGV crashes in processes that link libopenjp2.so.2.5.0
- Core dumps whose faulting frame resolves to symbols inside dwt.c such as opj_dwt_decode or related inverse transform functions
- Unexpected termination of image conversion daemons, PDF renderers, or thumbnailers immediately after receiving a .jp2, .j2k, or .jpx file
Detection Strategies
- Inventory installed OpenJPEG packages and libraries and flag any instance at version 2.5.0 for remediation tracking
- Enable core dump collection on image processing hosts and alert on crashes whose stack trace contains OpenJPEG DWT symbols
- Inspect web application logs for uploads of JPEG 2000 files followed by worker process restarts or 502 responses from image services
Monitoring Recommendations
- Monitor process crash telemetry on servers that decode user-supplied images, including document scanners and PDF pipelines
- Track the Debian and other distribution security feeds for the vulnerable openjpeg2 package; see the Debian LTS Announcement
- Alert on abnormal volumes of JPEG 2000 files traversing mail gateways or upload endpoints, which may indicate DoS attempts
How to Mitigate CVE-2025-50952
Immediate Actions Required
- Identify all systems running OpenJPEG 2.5.0 and applications that statically link the affected library
- Restrict acceptance of JPEG 2000 files at ingress points until patched builds are deployed
- Apply distribution updates as they become available, prioritizing internet-facing image processing services
Patch Information
At the time of this writing, the upstream fix is tracked in the OpenJPEG project on GitHub. Consult the GitHub Issue Discussion for the current patch status and the Debian LTS Announcement for backported package versions. Rebuild and redeploy any application that statically links OpenJPEG once fixed source is available.
Workarounds
- Block or filter JPEG 2000 file types (.jp2, .j2k, .jpx) at web application firewalls and mail gateways where the format is not required
- Run image decoding in sandboxed worker processes with automatic restart so a crash does not disable the parent service
- Disable OpenJPEG-backed decoders in downstream applications where alternate codecs satisfy business requirements
# Verify installed OpenJPEG version on Debian-based systems
dpkg -l | grep -i openjpeg
apt-cache policy libopenjp2-7
# Upgrade to the patched package once published
sudo apt-get update
sudo apt-get install --only-upgrade libopenjp2-7
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
