CVE-2026-21878— BACnet Stack Improperly Limits Pathnames to a Restricted Directory
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I. Basic Information for CVE-2026-21878
Vulnerability Information
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Vulnerability Title
BACnet Stack Improperly Limits Pathnames to a Restricted Directory
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Source: NVD (National Vulnerability Database)
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: NVD (National Vulnerability Database)
Vulnerability Title
BACnet Stack 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
BACnet Stack是BACnet Stack开源的一个适用于嵌入式系统、Linux、MacOS、BSD 和 Windows 的 BACnet 开源协议栈 C 库。 BACnet Stack 1.5.0.rc3之前版本存在路径遍历漏洞，该漏洞源于文件写入功能未验证用户提供的文件路径，可能导致向任意目录写入文件。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| bacnet-stack | bacnet-stack | < 1.5.0.rc3 | - |
II. Public POCs for CVE-2026-21878
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|---|
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Same Patch Batch · bacnet-stack · 2026-02-13 · 3 CVEs total
| CVE-2026-21870 | 5.5 MEDIUM | The BACnet Protocol Stack library has an Off-by-one Stack-based Buffer Overflow in tokeniz |
| CVE-2026-26264 | BACnet Stack WriteProperty decoding length underflow leads to OOB read and crash |
IV. Related Vulnerabilities
Same product: bacnet-stack
- CVE-2026-41503
BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Pro - CVE-2026-41502
BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyM - CVE-2026-41475
BACnet Stack: Out-of-Bounds Read in WritePropertyMultiple De - CVE-2026-40279
BACnet Stack: Undefined-behavior signed left shift in `decod - CVE-2026-26264
BACnet Stack WriteProperty decoding length underflow leads t
Same vendor: bacnet-stack
- CVE-2026-41503
BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Pro - CVE-2026-41502
BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyM - CVE-2026-41475
BACnet Stack: Out-of-Bounds Read in WritePropertyMultiple De - CVE-2026-40279
BACnet Stack: Undefined-behavior signed left shift in `decod - CVE-2026-26264
BACnet Stack WriteProperty decoding length underflow leads t
Same weakness: CWE-22
- CVE-2026-8274
npitre cramfs-tools Directory cramfsck.c do_directory path t - CVE-2022-50956
WordPress Plugin amministrazione-aperta 3.7.3 Local File Rea - CVE-2026-8215
Industrial Application Software IAS Canias ERP RMI iasReques - CVE-2026-42605
AzuraCast: Path Traversal in `currentDirectory` Parameter En - CVE-2026-42574
apko dirFS has a symlink-following path traversal that allow
V. Comments for CVE-2026-21878
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