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CVE-2025-56233

HIGHCVSS 7.5/10EPSS 0.31%

Last modified

CVE-2025-56233 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.31% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.31%

22.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2025-56233?
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.
How severe is CVE-2025-56233?
CVE-2025-56233 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.
How do I fix CVE-2025-56233?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST