What’s Vulnerable › Vulnerabilities

CVE-2026-72347: netfilter: xt_connmark: reject invalid shift parameters

• Severity: high (CVSS 7.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_connmark: reject invalid shift parameters Revision 2 of the CONNMARK target accepts user-controlled shift parameters and applies them to 32-bit mark values in connmark_tg_shift(). A shift_bits value of 32 or more triggers an undefined-shift bug when the rule is evaluated. Invalid shift_dir values are also accepted and silently fall back to the left-shift path. Reject invalid revision-2 shift parameters in connmark_tg_check() so malformed rules fail at installation time, before they can reach the packet path.

Affected products

• Linux kernel: 4.17 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1b47026fb4b35bac850ad6e8a4ad7fc018e09ebc
• https://git.kernel.org/stable/c/230173cc6105bdfb2696d37e6e56687b003fbe63
• https://git.kernel.org/stable/c/4eef84b09a3836919360c4232b0f16651a155eec
• https://git.kernel.org/stable/c/8ace320ac4416f5e5fbcd065309fb2dfcce787b0
• https://git.kernel.org/stable/c/9657bb11a6376ab0a79f05d433713d6944111e9d
• https://git.kernel.org/stable/c/c3fa852d117b3fda72265e4230e3967db4a74fcf
• https://git.kernel.org/stable/c/d8ce63d928b457fba7ed1e302492dfd32293671c

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