Vulnerability Monitor

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CVE-2021-45098

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.

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts integrity (unauthorized modifications), for affected systems. Impacting 2 products from oisf, from debian organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-12-16T05:15:08.727

Last Modified

2025-11-03T20:15:51.557

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:P/A:N

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: PARTIAL
Availability Impact: NONE

Exploitability Score

10.0

Impact Score

2.9

Weaknesses

Type: Primary
NVD-CWE-noinfo

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	oisf	suricata	< 6.0.4	Yes
Operating System	debian	debian_linux	9.0	Yes
Operating System	debian	debian_linux	10.0	Yes
Operating System	debian	debian_linux	11.0	Yes

References

https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942 Release Notes, Vendor Advisory ([email protected])
https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df Patch, Third Party Advisory ([email protected])
https://github.com/OISF/suricata/releases Release Notes, Third Party Advisory ([email protected])
https://redmine.openinfosecfoundation.org/issues/4710 Exploit, Issue Tracking, Patch, Vendor Advisory ([email protected])
https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942 Release Notes, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/OISF/suricata/releases Release Notes, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2025/03/msg00029.html (af854a3a-2127-422b-91ae-364da2661108)
https://redmine.openinfosecfoundation.org/issues/4710 Exploit, Issue Tracking, Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For oisf's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.