CVE-2021-45098

What it is

An issue was discovered in Suricata before 6.0.4. It is possible to bypass/evade any HTTP-based signature by faking an RST TCP packet with random TCP options of the md5header from the client side. After the three-way handshake, it's possible to inject an RST ACK with a random TCP md5header option. Then, the client can send an HTTP GET request with a forbidden URL. The server will ignore the RST ACK and send the response HTTP packet for the client's request. These packets will not trigger a Suricata reject action.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data tampering.

Exploit odds

2.0% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-12-16 05:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:13 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.0% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-12-16 05:15 UTC

Last modified

2026-06-17 04:13 UTC

Exploit probability

2.0% · EPSS, next 30 days

Record status

Modified

Affected

• Oisf Suricata < 6.0.4
• Debian Linux 9.0
• Debian Linux 10.0
• Debian Linux 11.0

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-45098.md and follow it. Check whether this project is affected by CVE-2021-45098. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

Copy as ticket · More options · Status badge