CVE-2026-71855: Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring

Routine

MEDIUM 5.9REMOTEUPGRADE

CVE-2026-71855 is a medium-severity flaw (CVSS 5.9) affecting suricata. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 76%)
CISA exploited list	No
Weakness	CWE-697
Published	2026-09-18
Last modified	2026-09-28

Publisher (CNA): GitHub, Inc. · Vendor: oisf

Last updated 2026-09-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-18 21:18 UTCPublished CVE record published
2026-09-28 18:39 UTCUpdated Record last modified

oisf suricata UPGRADE

Affected: < 7.0.17 · >= 8.0.0 and < 8.0.6

Fixed in: 7.0.17, 8.0.6

Safe to downgrade to: a release before 8.0.0

1. Check installed version

apt-cache policy suricata || rpm -q suricata || suricata --version

2. UPGRADE to 7.0.17 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade suricata

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade suricata

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 8.0.0 (Debian / Ubuntu)

apt-cache madison suricata sudo apt install suricata=<VERSION_BEFORE_8.0.0> sudo apt-mark hold suricata

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list suricata sudo dnf downgrade suricata-<VERSION_BEFORE_8.0.0> sudo dnf versionlock add suricata

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-71855?

suricata: upgrade to 7.0.17, 8.0.6. Exact commands for each OS are on this page.

Is CVE-2026-71855 being exploited?

CVE-2026-71855 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-71855 affect?

CVE-2026-71855 affects suricata. Severity is medium (CVSS 5.9). 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 t

How urgent is CVE-2026-71855?

Priority 32/100. Remotely exploitable, no login, no user action

Software pages

Suricata and Snort vulnerabilities

Related CVEs

CVE-2026-31931 HIGH 7.5 UPGRADE Suricata is a network IDS, IPS and NSM engine
CVE-2026-31933 HIGH 7.5 UPGRADE Suricata is a network IDS, IPS and NSM engine
CVE-2026-31937 HIGH 7.5 UPGRADE Suricata is a network IDS, IPS and NSM engine
CVE-2026-31932 HIGH 7.5 UPGRADE Suricata is a network IDS, IPS and NSM engine
CVE-2026-31934 HIGH 7.5 UPGRADE Suricata is a network IDS, IPS and NSM engine

References

← Back to latest CVEs