---
id: "CVE-2026-128991"
page: "https://infrastack.ai/live/CVE-2026-128991"
kind: "vulnerability"
aliases: ["CVE-2026-128991"]
title: "xschem: crafted schematic file causes out-of-bounds read and crash"
severity: "medium"
cvss: 5.8
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["eda", "electronics", "other", "xschem"]
not_affected_if: ["trusted-files-only", "xschem-outside-version-range"]
published_at: "2026-11-13T15:17:45+00:00"
first_seen_at: "2026-11-13T15:46:20+00:00"
updated_at: "2026-11-13T15:48:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-128991", "first_seen_at": "2026-11-13T15:46:20+00:00"}]
exploit_sources: []
---

# xschem: crafted schematic file causes out-of-bounds read and crash

Link for people: https://infrastack.ai/live/CVE-2026-128991 (this .md is for agents)

xschem is an electronic schematic editor, and versions 2.9.9 through 3.4.7 mishandle embedded-symbol records that lack a preceding instance in read_xschem_file(). A crafted schematic file that starts with a "[" record makes xschem read memory below the instance array, causing a crash.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed xschem version with `xschem --version`
- Look for xschem in the sources you open or receive, and check whether it is one of the versions named above

## Fix

- Move to a version newer than `3.4.7`; the exact fixed version is unknown from the sources

## Timeline

- 2026-11-13T15:46:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-128991

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/xschem-2.9.9-through-3.4.7-out-of-bounds-read-via-read-xschem-file-embedded-symbol-record
- [fix] Patch: github.com https://github.com/StefanSchippers/xschem/commit/e29af39c6133c36bdaf66603fd663231e75517f1

## From the sources

xschem 2.9.9 through 3.4.7 contains an out-of-bounds read vulnerability in read_xschem_file() in src/save.c that mishandles embedded-symbol records lacking a preceding instance. Attackers can supply a crafted schematic beginning with a "[" record, causing xschem to read and dereference memory below the instance array and crash.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_