5.5

CVE-2025-39764: netfilter: ctnetlink: remove refcounting in expectation dumpers

Modified
AliasesUBUNTU-CVE-2025-39764DEBIAN-CVE-2025-39764CGA-24vp-mqj3-mhr4
Published 11-09-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-39764 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.17%
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 43 · Related 44
OPENSUSE-SU-2025:20081-1SUSE-SU-2025:03600-1SUSE-SU-2025:03601-1SUSE-SU-2025:03614-1SUSE-SU-2025:03633-1SUSE-SU-2025:03634-1

Timeline

  1. 11-09-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: remove refcounting in expectation dumpers Same pattern as previous patch: do not keep the expectation object alive via refcount, only store a cookie value and then use that as the skip hint for dump resumption. AFAICS this has the same issue as the one resolved in the conntrack dumper, when we do if (!refcount_inc_not_zero(&exp->use)) to increment the refcount, there is a chance that exp == last, which causes a double-increment of the refcount and subsequent memory leak.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.17%

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 04-10-2026

04-10-202603-11-2026

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

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu149 products
  • linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard5 products
  • linux-aws-6.12< 6.12.63-r0 | < 6.12.76-r0 | < 6.12.65-r1 | < 6.12.74-r1 | < 6.12.71-r0 | < 6.12.77-r0 | < 6.12.62-r2 | < 6.12.70-r0 | < 6.12.77-r1 | < 6.12.62-r1 | < 6.12.67-r0 | < 6.12.60-r4 | < 6.12.68-r1 | < 6.12.72-r0 | < 6.12.66-r0 | < 6.12.62-r0 | < 6.12.74-r0 | < 6.12.77-r2 | < 6.12.65-r2 | < 6.12.78-r0 | < 6.12.68-r0 | < 6.12.72-r1 | < 6.12.69-r0 | < 6.12.80-r0 | < 6.12.65-r0
  • linux-azure-6.12< 6.12.69-r0 | < 6.12.72-r0 | < 6.12.60-r3 | < 6.12.65-r2 | < 6.12.74-r1 | < 6.12.65-r1 | < 6.12.60-r4 | < 6.12.74-r0 | < 6.12.62-r0 | < 6.12.66-r0 | < 6.12.67-r0 | < 6.12.71-r0 | < 6.12.78-r0 | < 6.12.65-r4 | < 6.12.77-r2 | < 6.12.77-r1 | < 6.12.77-r0 | < 6.12.70-r0 | < 6.12.62-r1 | < 6.12.62-r2 | < 6.12.68-r0 | < 6.12.76-r0 | < 6.12.65-r3 | < 6.12.63-r0 | < 6.12.80-r0
  • linux-gcp-6.12< 6.12.77-r2 | < 6.12.60-r4 | < 6.12.74-r0 | < 6.12.67-r0 | < 6.12.65-r2 | < 6.12.70-r0 | < 6.12.65-r0 | < 6.12.74-r1 | < 6.12.62-r2 | < 6.12.77-r1 | < 6.12.77-r0 | < 6.12.66-r0 | < 6.12.68-r0 | < 6.12.76-r0 | < 6.12.65-r1 | < 6.12.62-r1 | < 6.12.60-r3 | < 6.12.71-r0 | < 6.12.78-r0 | < 6.12.68-r1 | < 6.12.62-r0 | < 6.12.63-r0 | < 6.12.69-r0 | < 6.12.72-r0 | < 6.12.80-r0
  • linux-qemu-6.12< 6.12.67-r0 | < 6.12.78-r0 | < 6.12.65-r2 | < 6.12.68-r0 | < 6.12.71-r0 | < 6.12.77-r2 | < 6.12.70-r0 | < 6.12.72-r0 | < 6.12.76-r0 | < 6.12.69-r0 | < 6.12.65-r1 | < 6.12.74-r1 | < 6.12.77-r1 | < 6.12.77-r0 | < 6.12.74-r0 | < 6.12.66-r0 | < 6.12.80-r0
  • linux-vmware-6.12< 6.12.80-r0 | < 6.12.71-r0 | < 6.12.72-r0 | < 6.12.74-r0 | < 6.12.69-r0 | < 6.12.77-r0 | < 6.12.65-r1 | < 6.12.68-r0 | < 6.12.74-r1 | < 6.12.67-r0 | < 6.12.77-r2 | < 6.12.76-r0 | < 6.12.65-r2 | < 6.12.70-r0 | < 6.12.66-r0 | < 6.12.68-r1 | < 6.12.78-r0 | < 6.12.77-r1
Linux2 products
  • linux≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < b05500444b8eb97644efdd180839a04a706be97c | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < bada48ad5b0590e318d0f79636ff62a2ef9f4955 | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < 64b7684042246e3238464c66894e30ba30c7e851 | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < 9e5021a906532ca16e2aac69c0607711e1c70b1f | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < 078d33c95bf534d37aa04269d1ae6158e20082d5 | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < a4d634ded4d3d400f115d84f654f316f249531c9 | ≥ cf6994c2b9812a9f02b99e89df411ffc5db9c779, < 1492e3dcb2be3aa46d1963da96aa9593e4e4db5a | 2.6.23
  • linux_kernel≥ 2.6.23, < 6.16.2 | 6.17:rc1
Debian1 product
  • linux< 6.1.170-1 | < 6.12.85-1 | < 6.16.3-1

4 vendors · 157 products

References

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