Openindiana, kernel SunOS 5.11 has a denial of service vulnerability.

published 2025-09-29 last yr. modified 2026-10-19 21d ago also EUVD-2025-31596

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits: 0; none known

Openindiana, kernel SunOS 5.11 has a denial of service vulnerability. For the processing of TCP packets with RST or SYN flag set, Openindiana has a wide acceptable range of sequence numbers. It does not require the sequence number to exactly match the next expected sequence value, just to be within the current receive window, which violates RFC5961. This flaw allows attackers to send multiple random TCP RST/SYN packets to hit the acceptable range of sequence numbers, thereby interrupting normal connections and causing a denial of service attack.

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CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: last yr. (2025-09-29)

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption

References

github.com /zq-star/TCP-Vuln-Report/blob/master/Openindiana%20minimal/tcp-rst-syn/openindiana-minimal-tcp-rst-syn.md

Sources

CVE List CVE-2025-56233
NVD CVE-2025-56233

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