CVE-2025-38732: debian linux — Fix

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.

Is your site exposed to CVE-2025-38732?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.9 — 5.10.241
linux	linux_kernel	5.11 — 5.15.190
linux	linux_kernel	5.16 — 6.1.149
linux	linux_kernel	6.2 — 6.6.103
linux	linux_kernel	6.7 — 6.12.44
linux	linux_kernel	6.13 — 6.16.4
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/51e8531371f90bee742c63775c9a568e5d6bf3c5 https://git.kernel.org/stable/c/7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8 https://git.kernel.org/stable/c/82ef97abf22790182f7d433c74960dfd61b99c33 https://git.kernel.org/stable/c/91a79b792204313153e1bdbbe5acbfc28903b3a5 https://git.kernel.org/stable/c/a0a3ace2a57887dac1e7c9a724846040c3e31868 https://git.kernel.org/stable/c/b32e1590a8d22cf7d7f965e46d5576051acf8e42 https://git.kernel.org/stable/c/b7a885ba25960c91db237c3f83b4285156789bce

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html https://cert-portal.siemens.com/productcert/html/ssa-032379.html

Frequently Asked Questions

What is CVE-2025-38732? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-38732? +

CVE-2025-38732 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-38732? +

CVE-2025-38732 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38732? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-9588 10.0

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability in Iron Mountain Archiving Services Inc. …

CVE-2025-57870 10.0

A SQL Injection vulnerability exists in Esri ArcGIS Server versions 11.3, 11.4 and 11.5 on Windows, Linux and Kubernetes. This …

CVE-2026-48286 10.0

Adobe Campaign Classic (ACC) versions 7.4.3 build 9396 and earlier are affected by an Incorrect Authorization vulnerability that could result …

CVE-2026-13782 10.0

Use after free in Browser in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the renderer …

CVE-2026-48303 10.0

Adobe Campaign Classic (ACC) versions 7.4.3 build 9394 and earlier are affected by an Incorrect Authorization vulnerability that could result …

CVE-2025-34028 10.0

The Commvault Command Center Innovation Release allows an unauthenticated actor to upload ZIP files that represent install packages that, when …

CVE-2025-38732