{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21878 exists.","fix":"No fix has been published for CVE-2026-21878 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-21878 is a high-severity path traversal vulnerability in bacnet-stack, published on 13 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21878 and fix it if it is affected.\n\nWhat it is: CVE-2026-21878 is a high-severity path traversal vulnerability in bacnet-stack, published on 13 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21878 exists.\n\nAffected product: bacnet-stack. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-21878/ (Markdown: https://insights.sbomify.com/CVE-2026-21878/index.md)","id":"CVE-2026-21878","markdown":"https://insights.sbomify.com/CVE-2026-21878/index.md","name":"CVE-2026-21878","record":{"aliases":["GHSA-p8rx-c26w-545j"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_modify"],"network_reachable":"yes","non_default_config":false,"product_category":"BACnet protocol stack","requires_auth":"none","summary":"Attackers can write files to arbitrary directories due to lack of path validation in the BACnet Stack library, potentially compromising embedded systems.","user_interaction":"not_required","vuln_class":"path_traversal"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"bacnet_stack","vendor":"bacnetstack"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"}],"description":"BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.5.0.rc3, a vulnerability has been discovered in BACnet Stack's file writing functionality where there is no validation of user-provided file paths, allowing attackers to write files to arbitrary directories. This affects apps/readfile/main.c and ports/posix/bacfile-posix.c. This vulnerability is fixed in 1.5.0.rc3.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":false,"headline":"BACnet Stack Improperly Limits Pathnames to a Restricted Directory","id":"CVE-2026-21878","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"path_traversal","year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Kanboard vulnerable to Open Redirect via protocol-relative URLs","id":"CVE-2026-21879"},"packages":[],"prev":{"headline":"n8n is vulnerable to Remote Code Execution via Arbitrary File Write","id":"CVE-2026-21877"},"products":["bacnet-stack"],"published":"2026-02-13","related":[{"cvss_score":9.1,"headline":"Memory corruption in n/a","id":"CVE-2023-51773","kev_date_added":null,"published":"2023-12-25"},{"cvss_score":8.7,"headline":"BACnet Stack: Out-of-Bounds Read in WritePropertyMultiple Decoder via Deprecated Tag Parser","id":"CVE-2026-41475","kev_date_added":null,"published":"2026-04-24"},{"cvss_score":8.7,"headline":"BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyMultiple Object ID Decoder","id":"CVE-2026-41502","kev_date_added":null,"published":"2026-04-24"},{"cvss_score":8.7,"headline":"BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser","id":"CVE-2026-41503","kev_date_added":null,"published":"2026-04-24"},{"cvss_score":7.8,"headline":"BACnet Stack WriteProperty decoding length underflow leads to OOB read and crash","id":"CVE-2026-26264","kev_date_added":null,"published":"2026-02-13"},{"cvss_score":7.5,"headline":"BACnet-stack MS/TP reply matcher OOB read","id":"CVE-2025-66624","kev_date_added":null,"published":"2025-12-05"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-02-13","vendors":["bacnet-stack"]},"summary":"Attackers can write files to arbitrary directories due to lack of path validation in the BACnet Stack library, potentially compromising embedded systems.","url":"https://insights.sbomify.com/CVE-2026-21878/"}