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CVE-2026-71855— Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state

Quick assessment

Affected
OISF suricata
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Suricata 是一种网络入侵检测系统（IDS）、入侵防御系统（IPS）和网络安全监控引擎。在 7.0.17 和 8.0.6 之前的版本中， 在比较流（flow）时，如果两个流的原始地址字、端口、协议、VLAN、递归级别、活动设备及哈希桶均一致，就可能将 IPv4 流和 IPv6 流视为相等，而忽略了 IP 地址族（family）的差异。因此，一个 IPv6 数据包可能会复用 IPv4 的流状态（或反之），从而导致错误的 flowbit 状态、检测绕过或仅基于 IP 的绕过。该问题已在 8.0.6 和 7.0.1

CVSS 5.9 · Medium
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I. Basic Information for CVE-2026-71855

Vulnerability Information
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Vulnerability Title
Suricata flow: IPv4/IPv6 hash collision can reuse wrong flow state
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
不充分的比较
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
OISF suricata >= 8.0.0, < 8.0.6 -

II. Public POCs for CVE-2026-71855

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III. Intelligence Information for CVE-2026-71855

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Patches & Fixes for CVE-2026-71855 (3)

Other References for CVE-2026-71855 (4)

Same Patch Batch · OISF · 2026-09-18 · 17 CVEs total

CVE-2026-57228 8.2 HIGH Suricata smtp/mime: heap out-of-bounds read quoted-printable decoder
CVE-2026-63446 7.5 HIGH Suricata app-layer: passed flows can retain transactions, causing resource exhaustion
CVE-2026-63447 7.5 HIGH Suricata ftp: crafted FTP traffic can cause quadratic CPU consumption
CVE-2026-63452 7.5 HIGH Suricata http1: repeated brotli compression bombs can cause excessive CPU consumption
CVE-2026-57227 7.5 HIGH Suricata mqtt: unbounded resource consumption from repeated pubrec and pubrel messages
CVE-2026-71418 7.5 HIGH Suricata doh2: crafted HTTP/2 DATA frames can cause quadratic CPU consumption
CVE-2026-57223 7.0 HIGH Suricata windows: unquoted LocalSystem service ImagePath can allow local privilege escalat
CVE-2026-57224 6.5 MEDIUM Suricata dhcp: unbounded transactions in unidirectional traffic can lead to resource exhau
CVE-2026-63448 5.9 MEDIUM Suricata smb: some SMB flows can cause resource exhaustion
CVE-2026-57229 5.3 MEDIUM Suricata smtp/mime: incomplete state reset allows detection bypass
CVE-2026-57222 5.3 MEDIUM Suricata ippair: hash collision can cause incorrect state reuse across IPv4 and IPv6
CVE-2026-63450 3.7 LOW Suricata ftp: RETR/STOR before PORT/PASV can disable further IDS app-layer detection
CVE-2026-63449 3.7 LOW Suricata sip: large SIP message bodies can evade detection with frame keyword
CVE-2026-57226 3.7 LOW Suricata swf: heap buffer overflow in SWF decompression depth handling
CVE-2026-63451 3.3 LOW Suricata detect: frame rules without content and with transform can cause heap buffer over
CVE-2026-57225 3.3 LOW Suricata datasets: NULL pointer dereference in JSON/NDJSON dataset loading

IV. Related Vulnerabilities

Same product: suricata
Same vendor: OISF
Same weakness: CWE-697

V. Comments for CVE-2026-71855

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