CVE-2025-66221: Icloudpd · Werkzeug safe_join() allows Windows special device names
Affects icloudpdSource GCVE Database
Not known to be exploited · CVSS 6.3 Medium : upgrade to 1.32.3 when convenient.
Data as of 9 Nov 2026, 19:48 UTC
- Patch
- Available – fixed in 1.32.3
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Upgrade icloudpd to 1.32.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewicloudpdpkg:brew/icloudpdOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade icloudpd to version 1.32.3 or later, where the vulnerability is fixed. No other mitigation is indicated or required.
Description
The vulnerability in icloudpd arises from Werkzeug's safe_join function, which improperly allows Windows special device names like CON and AUX in path segments. On Windows systems, these device names exist implicitly in every directory and can be opened but cause reading operations to hang indefinitely. This affects icloudpd versions from 1.21.0 up to but not including 1.32.3. A fix is available in version 1.32.3.
References
- github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2025-66221 (opens in a new tab)
- github.com/pallets/werkzeug/commit/4b833376a45c323a189cd11d2362bcffdb1c0c13 (opens in a new tab)
- github.com/pallets/werkzeug (opens in a new tab)
- github.com/pallets/werkzeug/releases/tag/3.1.4 (opens in a new tab)