CVE-2026-120596: Ethernut / egnite Nut/Net TCP/IP Stack · Infinite Loop
Affects Ethernut / egnite Nut/Net TCP/IP StackSource CVE Database V5
Not known to be exploited · CVSS 7.5 High.
Data as of 2 Nov 2026, 17:43 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 7.5 |
|---|
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers can reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-02.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Nov 2026
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 2 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Ethernut / egnite GmbHNut/Net TCP/IP Stack | Affected
| Fixed in– |
AI-suggested
Until a fix is available, network-level filtering to block malformed TCP segments with unknown options of zero length may mitigate exploitation. Rebooting the device restores normal operation after an attack.
Description
CVE-2026-120596 is a denial-of-service vulnerability in the Nut/Net TCP/IP stack used in Nut/OS by Ethernut/Egnite. The flaw allows an unauthenticated attacker to send a specially crafted TCP segment with an unknown TCP option length of zero, causing an infinite loop in the TCP options parser. This infinite loop blocks the TCP processing thread, making all TCP services on the device unresponsive until reboot. The vulnerability affects Nut/OS versions up to 5.1.