5.5

CVE-2025-38732: netfilter: nf_reject: don't leak dst refcount for loopback packets

Modified
AliasesUBUNTU-CVE-2025-38732DEBIAN-CVE-2025-38732
Published 05-09-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-38732 is a medium (CVSS 5.5) vulnerability in debian debian_linux. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 6.7% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.18%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 47 · Related 41
DLA-4327-1DLA-4328-1DSA-6008-1DSA-6009-1MGASA-2025-0234MGASA-2025-0235

Timeline

  1. 05-09-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

7%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.17% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu136 products
  • linux< 5.15.0-163.173 | < 6.8.0-100.100
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.15.0-1097.104 | < 6.8.0-1046.49
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linux< 6.1.153-1 | < 6.12.48-1 | < 6.16.5-1
  • debian_linuxEOL11.0
Linux2 products
  • linux≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < 7b8b503c06274ef3c6c1a107743f1ec0d0a53ef8 | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < 82ef97abf22790182f7d433c74960dfd61b99c33 | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < b7a885ba25960c91db237c3f83b4285156789bce | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < a0a3ace2a57887dac1e7c9a724846040c3e31868 | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < 51e8531371f90bee742c63775c9a568e5d6bf3c5 | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < b32e1590a8d22cf7d7f965e46d5576051acf8e42 | ≥ f53b9b0bdc59c0823679f2e3214e0d538f5951b9, < 91a79b792204313153e1bdbbe5acbfc28903b3a5 | 5.9
  • linux_kernel≥ 5.9, < 5.10.241 | ≥ 5.11, < 5.15.190 | ≥ 5.16, < 6.1.149 | ≥ 6.2, < 6.6.103 | ≥ 6.7, < 6.12.44 | ≥ 6.13, < 6.16.4 | 6.17:rc1 | 6.17:rc2

3 vendors · 140 products

References

42 links
Show all 42 references