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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...

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
None

Exploit likelihood

1.96%Up 0.9 points since Dec 16, 2021
90%50%10%1%

What each source reports

NVD Score used 7.5

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.

Record
CVE-2021-45098
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2021-45098
Updated
2026-11-02
EUVDEUVD-2021-31889 No score

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.

Record
EUVD-2021-31889
Updated
2026-11-02
GitHub AdvisoriesGHSA-cfcf-x7x2-gpf8 7.5

An issue was discovered in Suricata before 6.0.4. It is possible to bypass/evade any HTTP-based...

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.

Record
GHSA-cfcf-x7x2-gpf8
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVALPINE-CVE-2021-45098 7.5

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.

Record
ALPINE-CVE-2021-45098
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-03
OSV 7.5

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.

Record
CVE-2021-45098
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVDEBIAN-CVE-2021-45098 7.5

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.

Record
DEBIAN-CVE-2021-45098
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2021-45098 7.5

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.

Record
UBUNTU-CVE-2021-45098
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
suricata
Alpine:v3.15
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.16
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.17
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.18
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.19
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.20
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.21
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.22
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.23
before 6.0.4-r0
6.0.4-r0
suricata
Alpine:v3.24
before 6.0.4-r0
6.0.4-r0
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Affected packages
PackageAffectedFixed
suricata
Debian:13
before 1:6.0.4-1
1:6.0.4-1
suricata
Debian:14
before 1:6.0.4-1
1:6.0.4-1
suricata
Debian:11
From an advisory covering 7 CVEs
before 1:6.0.1-3+deb11u1, plus listed versions
1:6.0.1-3
1:6.0.1-3+deb11u1
suricata
Ubuntu:16.04:LTS
All versions, plus listed versions
2.0.8-1build12.0.9-12.0.10-12.0.10-22.0.11-13.0-1
None known
suricata
Ubuntu:18.04:LTS
All versions, plus listed versions
3.2-2ubuntu3
None known

History

History
RecordedChangedSources
affected, facts
affected, aliases, referencesOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-45098 is a high vulnerability (CVSS 7.5) in Oisf Suricata, published December 16, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.96%, the 80th percentile. Fixed in suricata 6.0.4-r0.

References

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