What this actually is.
Technical background, root cause, and affected surface.
In the DSI OpenSession handler, a switch/case statement is missing a break statement, causing execution to fall through from one option handler to the next. An attacker can send a crafted DSI OpenSession request that triggers the fall-through path, executing unintended code during AFP session setup.
- Vendor
- Netatalk
- Product
- Netatalk
- Severity
- Low
- CVSS Score
- 3.7
- Status
- Published
- CWE
- CWE-484: Omitted Break Statement in Switch
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
From one request
to root shell.
Reproduced in a sandboxed environment. Requires only LAN or WiFi adjacency.
The bug, and the fix.
libatalk/dsi/dsi_opensess.c: switch(option) block missing break between cases, causing fallthrough to next case handler
Root cause: Missing break statement in switch/case block in DSI OpenSession option processing
When does this fire?
All conditions must be true for the exploit to succeed.
Attacker sends a DSI OpenSession request with a specific option value that triggers the fall-through case
What an attacker does to you.
Post-exploitation outcomes mapped to CVSS impact metrics.
Unintended code path execution during AFP session establishment; minor DoS
Fix it. In this order.
A runbook, not a checklist. Sequence matters — assume compromise before you act.
Upgrade to Netatalk 4.4.3 which adds the missing break statement.
disclose@securin.ioVendors moved in days.
Attackers in hours.
Reconstructed from vendor advisories, CISA bulletins, and Securin research records.
2026-05-13: Netatalk 4.4.3 patch released | 2026-05-21: CVE published to MITRE
Timeline recorded · Disclosure coordinated by Securin
Cite, verify, go deeper.
Primary sources — NVD, CISA KEV, and machine-readable IoC feed.