CVE-2026-72347
HighCVSS 7.3Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel, the netfilter xt_connmark module (revision 2) lacks validation of shift parameters. A shift_bits value of 32 or more triggers an undefined shift, and invalid shift_dir values are accepted and silently fall back to left shift. The fix rejects invalid parameters in connmark_tg_check() so errors are caught at rule installation time.
Risk Assessment
Malformed connmark rules can cause kernel crashes or unpredictable behavior, potentially leading to service disruption or security bypass.
Recommendation
Install the Linux kernel update containing the fix for CVE-2026-72347. Before deployment, verify shift parameters in connmark rules.
Original NVD description (English source)
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.