CVE-2026-31681— netfilter: xt_multiport: validate range encoding in checkentry
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 12
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | a89ecb6a2ef732d04058d87801e2b6bd7e5c7089< 36bf0d98e180a7c384c8d8a59b0d2d4b80e5eb16 | affected |
a89ecb6a2ef732d04058d87801e2b6bd7e5c7089< aec14808271f2bf2b656de6ff12dfe73c5fd3b67 | affected | ||
a89ecb6a2ef732d04058d87801e2b6bd7e5c7089< 8368ce8eb01f0b91111d814703696e780d0ef12f | affected | ||
a89ecb6a2ef732d04058d87801e2b6bd7e5c7089< 1e4baa853f1cc4227e04f52d6860524707cfb294 | affected | ||
a89ecb6a2ef732d04058d87801e2b6bd7e5c7089< ff64c5bfef12461df8450e0f50bb693b5269c720 | affected | ||
2.6.17 | affected | ||
< 2.6.17 | unaffected | ||
6.6.136≤ 6.6.* | unaffected | ||
| … +4 more rows | |||
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I. Basic Information for CVE-2026-31681
Vulnerability Information
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Vulnerability Title
netfilter: xt_multiport: validate range encoding in checkentry
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_multiport: validate range encoding in checkentry ports_match_v1() treats any non-zero pflags entry as the start of a port range and unconditionally consumes the next ports[] element as the range end. The checkentry path currently validates protocol, flags and count, but it does not validate the range encoding itself. As a result, malformed rules can mark the last slot as a range start or place two range starts back to back, leaving ports_match_v1() to step past the last valid ports[] element while interpreting the rule. Reject malformed multiport v1 rules in checkentry by validating that each range start has a following element and that the following element is not itself marked as another range start.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于xt_multiport中范围编码未在checkentry验证，可能导致越界解析端口数组。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-31681
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-31681 (1)
Same Patch Batch · Linux · 2026-04-25 · 13 CVEs total
| CVE-2026-31685 | 9.4 CRITICAL | netfilter: ip6t_eui64: reject invalid MAC header for all packets |
| CVE-2026-31682 | 9.1 CRITICAL | bridge: br_nd_send: linearize skb before parsing ND options |
| CVE-2026-31683 | 7.8 HIGH | batman-adv: avoid OGM aggregation when skb tailroom is insufficient |
| CVE-2026-31680 | 7.8 HIGH | net: ipv6: flowlabel: defer exclusive option free until RCU teardown |
| CVE-2026-31678 | 7.8 HIGH | openvswitch: defer tunnel netdev_put to RCU release |
| CVE-2026-31675 | 7.8 HIGH | net/sched: sch_netem: fix out-of-bounds access in packet corruption |
| CVE-2026-31673 | 7.8 HIGH | af_unix: read UNIX_DIAG_VFS data under unix_state_lock |
| CVE-2026-31676 | 7.5 HIGH | rxrpc: only handle RESPONSE during service challenge |
| CVE-2026-31679 | 7.1 HIGH | openvswitch: validate MPLS set/set_masked payload length |
| CVE-2026-31674 | 7.1 HIGH | netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check() |
| CVE-2026-31684 | net: sched: act_csum: validate nested VLAN headers | |
| CVE-2026-31677 | crypto: af_alg - limit RX SG extraction by receive buffer budget |
IV. Related Vulnerabilities
V. Comments for CVE-2026-31681
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