Riskcovery

CVE-2025-38732

netfilter: nf_reject: don't leak dst refcount for loopback packets

State
Published
Severity
Not scored
Published
Sep 5, 2025
Updated
Oct 15, 2026
Reserved
Apr 16, 2025

Read the record on cve.org

Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_reject: don't leak dst refcount for loopback packets

recent patches to add a WARN() when replacing skb dst entry found an old bug:

WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline] WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline] WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234 [..] Call Trace: nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325 nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] ..

This is because blamed commit forgot about loopback packets. Such packets already have a dst_entry attached, even at PRE_ROUTING stage.

Instead of checking hook just check if the skb already has a route attached to it.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

ProductVersions
LinuxLinux
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before 7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8Affected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before 82ef97abf22790182f7d433c74960dfd61b99c33Affected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before b7a885ba25960c91db237c3f83b4285156789bceAffected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before a0a3ace2a57887dac1e7c9a724846040c3e31868Affected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before 51e8531371f90bee742c63775c9a568e5d6bf3c5Affected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before b32e1590a8d22cf7d7f965e46d5576051acf8e42Affected
  • f53b9b0bdc59c0823679f2e3214e0d538f5951b9 to before 91a79b792204313153e1bdbbe5acbfc28903b3a5Affected
LinuxLinux
  • 5.9Affected
  • before 5.9Not affected
  • 5.10.241 through 5.10.*Not affected
  • 5.15.190 through 5.15.*Not affected
  • 6.1.149 through 6.1.*Not affected
  • 6.6.103 through 6.6.*Not affected
  • 6.12.44 through 6.12.*Not affected
  • 6.16.4 through 6.16.*Not affected
  • 6.17 and laterNot affected

References

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