CVE-2026-21860 is a vulnerability in Werkzeug, a WSGI web application library, affecting versions prior to 3.1.5. Specifically, its safe_join function on Windows systems incorrectly handles path segments containing Windows device names with file extensions or trailing spaces, such as "CON.txt" or "CON ". This medium-severity vulnerability (CVSS 5.3) allows for a denial of service (A:L) due to the implicit presence and readability of these special device names in every directory. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 3.1.5CPE matchmatch criteria | cpe:2.3:a:palletsprojects:werkzeug:*:*:*:*:*:*:*:* |
CVSS version used by this source: 4.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.