CVE-2026-71855
Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
CVE-2026-71855- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-697
- Updated
- 2026-11-02
EUVDEUVD-2026-83398
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
EUVD-2026-83398- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
NVD
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
CVE-2026-71855- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-697
- Updated
- 2026-11-02
OSV
Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
CVE-2026-71855- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-697
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-71855
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
DEBIAN-CVE-2026-71855- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-71855
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, src/flow-hash.c can treat an IPv4 and IPv6 flow as equal without comparing the IP family when their raw address words, ports, protocol, VLAN, recursion level, live device, and hash bucket align. An IPv6 packet can therefore reuse IPv4 flow state or the reverse, causing incorrect flowbit state, detection bypass, or IP-only bypass. This issue is fixed in versions 8.0.6 and 7.0.17.
- Record
UBUNTU-CVE-2026-71855- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 3.1
- 7.5 High
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
suricataDebian:13 |
All versions, plus listed versions 1:7.0.10-11:7.0.10-1+deb13u11:7.0.10-1+deb13u21:7.0.10-1+deb13u31:7.0.10-1+deb13u4 Show 24 moreShow less1:7.0.11-11:7.0.11-1~bpo13+11:8.0.0-1~exp11:8.0.0-1~exp21:8.0.0-1~exp41:8.0.0-1~exp51:8.0.1-11:8.0.1-21:8.0.1-31:8.0.1-3~bpo13+11:8.0.2-11:8.0.2-1~bpo13+11:8.0.3-11:8.0.3-1~bpo13+11:8.0.3-2~exp11:8.0.4-11:8.0.4-1~bpo13+11:8.0.5-11:8.0.5-1~bpo13+11:8.0.6-11:8.0.6-1~bpo13+11:8.0.7-11:8.0.7-1~bpo13+11:8.0.7-2~exp1 |
None known |
suricataDebian:14 |
before 1:8.0.6-1, plus listed versions 1:7.0.10-11:7.0.11-11:7.0.11-1~bpo13+11:8.0.0-1~exp11:8.0.0-1~exp2 Show 16 moreShow less1:8.0.0-1~exp41:8.0.0-1~exp51:8.0.1-11:8.0.1-21:8.0.1-31:8.0.1-3~bpo13+11:8.0.2-11:8.0.2-1~bpo13+11:8.0.3-11:8.0.3-1~bpo13+11:8.0.3-2~exp11:8.0.4-11:8.0.4-1~bpo13+11:8.0.5-11:8.0.5-1~bpo13+11:8.0.6-1~bpo13+1 |
1:8.0.6-1 |
suricataUbuntu: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 |
suricataUbuntu:18.04:LTS |
All versions, plus listed versions 3.2-2ubuntu3 |
None known |
suricataUbuntu:22.04:LTS |
All versions, plus listed versions 1:6.0.4-21:6.0.4-3 |
None known |
suricataUbuntu:24.04:LTS |
All versions, plus listed versions 1:7.0.0-21:7.0.2-11:7.0.2-1build11:7.0.3-1build11:7.0.3-1build3 |
None known |
suricataUbuntu:26.04:LTS |
All versions, plus listed versions 1:7.0.10-11:8.0.1-3build11:8.0.2-11:8.0.2-1build11:8.0.3-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-71855 is a medium vulnerability (CVSS 5.9) in Oisf Suricata, published September 18, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.31%, the 23rd percentile. Fixed in suricata 1:8.0.6-1.
References
github.com/OISF/suricata/security/advisories/GHSA-fvwh-wjcq-2586