CVE-2025-38732netfilter: nf_reject: don't leak dst refcount for loopback packets
Updated under an hour ago ()
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It affects Linux and 6 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before 7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before 82ef97abf22790182f7d433c74960dfd61b99c33; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before b7a885ba25960c91db237c3f83b4285156789bce; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before a0a3ace2a57887dac1e7c9a724846040c3e31868; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before 51e8531371f90bee742c63775c9a568e5d6bf3c5; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before b32e1590a8d22cf7d7f965e46d5576051acf8e42; from f53b9b0bdc59c0823679f2e3214e0d538f5951b9 before 91a79b792204313153e1bdbbe5acbfc28903b3a5 | CNA record |
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name) | before V5.0 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.9 before 5.10.241; from 5.11 before 5.15.190; from 5.16 before 6.1.149; from 6.2 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.16.4; 6.17; 6.17 | NVD |
debian debian_linux debian:debian_linux | 11.0 | NVD |
References
- https://git.kernel.org/stable/c/7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8patch
- https://git.kernel.org/stable/c/82ef97abf22790182f7d433c74960dfd61b99c33patch
- https://git.kernel.org/stable/c/b7a885ba25960c91db237c3f83b4285156789bcepatch
- https://git.kernel.org/stable/c/a0a3ace2a57887dac1e7c9a724846040c3e31868patch
- https://git.kernel.org/stable/c/51e8531371f90bee742c63775c9a568e5d6bf3c5patch
- https://git.kernel.org/stable/c/b32e1590a8d22cf7d7f965e46d5576051acf8e42patch
- https://git.kernel.org/stable/c/91a79b792204313153e1bdbbe5acbfc28903b3a5patch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.htmlmailing-list, third-party-advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlmailing-list, third-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.