critical CVSS 9.1

CVE-2026-54058·Python vulnerability

Pillow is a Python imaging library. Prior to 12.3.0, when Pillow loads an uncompressed McIdas AREA image from a filename through the mmap raw codec path, attacker-controlled header words can set a row stride smaller than the natural row width, causing pixel access such as Image.tobytes(), getpixel, convert, or save to read beyond the mapped region and disclose adjacent process memory or fault. This issue is fixed in version 12.3.0.

Severity
critical
Software
Python
Fixed in
12.3.0
Published
2026-07-14

Affected versions

Until: 12.3.0

Fixed in: 12.3.0

How to fix this CVE

Update Pillow to version 12.3.0 or later to remediate a critical memory disclosure vulnerability in the McIdas AREA image codec. The vulnerability allows attackers to read adjacent process memory by manipulating image headers when loading uncompressed AREA files. Ensure all Python environments using Pillow are patched immediately.

sudo dnf update python3-pillow

Defensia detects this vulnerability

How to check if you are affected

  1. Run `python3 -c "from PIL import __version__; print(__version__)"` to check the installed Pillow version and verify it is 12.3.0 or higher
  2. Search application logs and configuration files for references to McIdas AREA image processing or use of `mmap` raw codec paths: `grep -r "AREA\|mmap" /var/log/ /etc/ --include="*.log" --include="*.conf"`
  3. Check Python process memory for unexpected access patterns by monitoring system calls: `strace -e mmap,mprotect -p <pid> 2>&1 | grep -i "stride\|area"`
  4. Verify the patch was applied by confirming Pillow version is 12.3.0+: `pip show Pillow | grep Version`

FAQ

What is CVE-2026-54058?

CVE-2026-54058 is a critical memory disclosure vulnerability in Pillow's McIdas AREA image decoder that allows attackers to read arbitrary adjacent process memory by crafting malicious image headers with undersized row strides, causing out-of-bounds reads during image processing operations.

Is CVE-2026-54058 being actively exploited?

No, CVE-2026-54058 is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, and no public exploits are currently available. However, the critical severity warrants immediate patching.

What versions of Python are affected by CVE-2026-54058?

The vulnerability affects Pillow versions prior to 12.3.0. All Python installations using affected Pillow versions are vulnerable when processing McIdas AREA images from untrusted sources.

How do I check if my server is vulnerable to CVE-2026-54058?

Execute `pip show Pillow | grep Version` to check the installed version; if it is below 12.3.0, your system is vulnerable. Additionally, audit applications that process image files to identify if they handle McIdas AREA format.

Does Defensia detect CVE-2026-54058?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Pillow is installed on a monitored server, CVE-2026-54058 will appear in your dashboard with remediation steps.

Related Python CVEs

CVE-2026-33054CVSS 10Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
CVE-2026-25632CVSS 10EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.
CVE-2026-28505CVSS 10Tautulli is a Python based monitoring and tracking tool for Plex Media Server. Prior to version 2.17.0, the str_eval() function in notification_handler.py implements a sandboxed eval() for notification text templates. The sandbox attempts to restrict callable names by inspecting code.co_names of the compiled code object. However, co_names only contains names from the outer code object. When a lambda expression is used, it creates a nested code object whose attribute accesses are stored in code.co_consts, NOT in code.co_names. The sandbox never inspects nested code objects. This issue has been patched in version 2.17.0.
CVE-2026-34938CVSS 10PraisonAI is a multi-agent teams system. Prior to version 1.5.90, execute_code() in praisonai-agents runs attacker-controlled Python inside a three-layer sandbox that can be fully bypassed by passing a str subclass with an overridden startswith() method to the _safe_getattr wrapper, achieving arbitrary OS command execution on the host. This issue has been patched in version 1.5.90.
CVE-2026-26030CVSS 9.9Semantic Kernel, Microsoft's semantic kernel Python SDK, has a remote code execution vulnerability in versions prior to 1.39.4, specifically within the `InMemoryVectorStore` filter functionality. The problem has been fixed in version `python-1.39.4`. Users should upgrade this version or higher. As a workaround, avoid using `InMemoryVectorStore` for production scenarios.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-54058. Free for 1 server.

Get started free