CVE-2025-38732
MediumIn 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 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected versions
Linux kernel versions
5.9
and later are affected. Fixed in
5.10.241,
5.15.190,
6.1.149,
6.6.103,
6.12.44,
6.16.4,
6.17
and their respective stable series.
References
The following references provide additional information about CVE-2025-38732 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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Mailing List Third Party Advisory
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Mailing List Third Party Advisory
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PatchKernel patch commithttps://git.kernel.org/stable/c/51e8531371f90bee742c63775c9a568e5d6bf3c5
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PatchKernel patch commithttps://git.kernel.org/stable/c/7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8
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PatchKernel patch commithttps://git.kernel.org/stable/c/82ef97abf22790182f7d433c74960dfd61b99c33
Frequently asked questions
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What is CVE-2025-38732?
CVE-2025-38732 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.9 onward and has been patched in 5.10.241, 5.15.190, 6.1.149 and others. CVE-2025-38732 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2025-38732?
CVE-2025-38732 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2025-38732?
Yes — CVE-2025-38732 has been patched. Fixed versions include 5.10.241, 5.15.190, 6.1.149 and others. If you are running Linux kernel 5.9 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-38732 actively exploited?
No — CVE-2025-38732 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.