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Fencer Vulns
high 7.8

CVE-2025-39797 json

xfrm: Duplicate SPI Handling

published 2025-09-12 13 mo ago modified 2026-11-05 3 d ago also EUVD-2025-29057

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

xfrm: Duplicate SPI Handling

The issue originates when Strongswan initiates an XFRM_MSG_ALLOCSPI Netlink message, which triggers the kernel function xfrm_alloc_spi(). This function is expected to ensure uniqueness of the Security Parameter Index (SPI) for inbound Security Associations (SAs). However, it can return success even when the requested SPI is already in use, leading to duplicate SPIs assigned to multiple inbound SAs, differentiated only by their destination addresses.

This behavior causes inconsistencies during SPI lookups for inbound packets. Since the lookup may return an arbitrary SA among those with the same SPI, packet processing can fail, resulting in packet drops.

According to RFC 4301 section 4.4.2 , for inbound processing a unicast SA is uniquely identified by the SPI and optionally protocol.

Reproducing the Issue Reliably: To consistently reproduce the problem, restrict the available SPI range in charon.conf : spi_min = 0x10000000 spi_max = 0x10000002 This limits the system to only 2 usable SPI values. Next, create more than 2 Child SA. each using unique pair of src/dst address. As soon as the 3rd Child SA is initiated, it will be assigned a duplicate SPI, since the SPI pool is already exhausted. With a narrow SPI range, the issue is consistently reproducible. With a broader/default range, it becomes rare and unpredictable.

Current implementation: xfrm_spi_hash() lookup function computes hash using daddr, proto, and family. So if two SAs have the same SPI but different destination addresses, then they will: a. Hash into different buckets b. Be stored in different linked lists (byspi + h) c. Not be seen in the same hlist_for_each_entry_rcu() iteration. As a result, the lookup will result in NULL and kernel allows that Duplicate SPI

Proposed Change: xfrm_state_lookup_spi_proto() does a truly global search - across all states, regardless of hash bucket and matches SPI and proto.

Patch / fix

  • Linux Linux 6.1.191, 6.6.103, 6.12.43, 6.15.11, 6.16.2, 6.17
  • linux Debian 13 6.12.43-1
  • linux Debian 14 6.16.3-1

debian advisories DEBIAN-CVE-2025-39797

  • linux Ubuntu 24.04 LTS 6.8.0-100.100
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1044.44
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1046.52
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1030.33
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1047.51

ubuntu advisories UBUNTU-CVE-2025-39797

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.31.1.el9_8
  • rv RHEL 9 5.14.0-687.31.1.el9_8
  • perf RHEL 9 5.14.0-687.31.1.el9_8
  • rtla RHEL 9 5.14.0-687.31.1.el9_8
  • libperf RHEL 9 5.14.0-687.31.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.31.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.31.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.31.1.el9_8

red hat advisories RHSA-2026:47040RHSA-2026:18134

  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.127.1
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.127.1
  • kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.127.1
  • kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.127.1
  • kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.127.1
  • kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.127.1.150500.6.61.1
  • kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1
  • kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.58.1

suse advisories SUSE-SU-2025:4320-1SUSE-SU-2025:4301-1SUSE-SU-2025:21080-1SUSE-SU-2025:21147-1SUSE-SU-2025:21180-1SUSE-SU-2026:20561-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.7.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.7.1

opensuse advisories openSUSE-SU-2025:20091-1openSUSE-SU-2025:20081-1

  • kernel AlmaLinux 9 5.14.0-687.31.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.31.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.31.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.31.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.31.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.31.1.el9_8

almalinux advisories ALSA-2026:47040ALSA-2026:18134

  • kernel Rocky Linux 9 5.14.0-687.31.1.el9_8

rocky linux advisories RLSA-2026:47040

  • kernel Azure Linux 3.0 6.6.104.2-1

azure linux advisories AZL-67334

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-39797 updated cvss 5.3

kernel: xfrm: Duplicate SPI Handling

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.152.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.152.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.152.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.152.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.152.1.el9_6
    fixed: vendor fix RHSA-2026:91492
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.31.1.el9_8, perf 5.14.0-687.31.1.el9_8, rtla 5.14.0-687.31.1.el9_8, python3-perf 5.14.0-687.31.1.el9_8, kernel-devel-matched 5.14.0-687.31.1.el9_8, kernel-64k-devel-matched 5.14.0-687.31.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.7.1.el10_2, perf 6.12.0-211.7.1.el10_2, rtla 6.12.0-211.7.1.el10_2, python3-perf 6.12.0-211.7.1.el10_2, kernel-devel-matched 6.12.0-211.7.1.el10_2, kernel-64k-devel-matched 6.12.0-211.7.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.158.1.el9_4, perf 5.14.0-427.158.1.el9_4, rtla 5.14.0-427.158.1.el9_4, kernel-devel-matched 5.14.0-427.158.1.el9_4, kernel-64k-devel-matched 5.14.0-427.158.1.el9_4, kernel-debug-devel-matched 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.117.1.el10_0, perf 6.12.0-55.117.1.el10_0, rtla 6.12.0-55.117.1.el10_0, python3-perf 6.12.0-55.117.1.el10_0, kernel-devel-matched 6.12.0-55.117.1.el10_0, kernel-64k-devel-matched 6.12.0-55.117.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.152.1.el9_6, perf 5.14.0-570.152.1.el9_6, rtla 5.14.0-570.152.1.el9_6, python3-perf 5.14.0-570.152.1.el9_6, kernel-devel-matched 5.14.0-570.152.1.el9_6, kernel-64k-devel-matched 5.14.0-570.152.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:91492
show 18 more
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.31.1.el9_8, kernel-64k 5.14.0-687.31.1.el9_8, kernel-core 5.14.0-687.31.1.el9_8, kernel-tools 5.14.0-687.31.1.el9_8, kernel-modules 5.14.0-687.31.1.el9_8, kernel-64k-core 5.14.0-687.31.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.7.1.el10_2, kernel-64k 6.12.0-211.7.1.el10_2, kernel-core 6.12.0-211.7.1.el10_2, kernel-tools 6.12.0-211.7.1.el10_2, kernel-modules 6.12.0-211.7.1.el10_2, kernel-64k-core 6.12.0-211.7.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.158.1.el9_4, kernel 5.14.0-427.158.1.el9_4, kernel-64k 5.14.0-427.158.1.el9_4, kernel-core 5.14.0-427.158.1.el9_4, kernel-tools 5.14.0-427.158.1.el9_4, python3-perf 5.14.0-427.158.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.117.1.el10_0, kernel-64k 6.12.0-55.117.1.el10_0, kernel-core 6.12.0-55.117.1.el10_0, kernel-tools 6.12.0-55.117.1.el10_0, kernel-modules 6.12.0-55.117.1.el10_0, kernel-64k-core 6.12.0-55.117.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.152.1.el9_6, kernel-64k 5.14.0-570.152.1.el9_6, kernel-core 5.14.0-570.152.1.el9_6, kernel-tools 5.14.0-570.152.1.el9_6, kernel-modules 5.14.0-570.152.1.el9_6, kernel-64k-core 5.14.0-570.152.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:91492
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.31.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.31.1.el9_8
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.7.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.7.1.el10_2
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.117.1.el10_0
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.31.1.el9_8, kernel-rt-64k 5.14.0-687.31.1.el9_8, kernel-rt-core 5.14.0-687.31.1.el9_8, kernel-rt-modules 5.14.0-687.31.1.el9_8, kernel-rt-64k-core 5.14.0-687.31.1.el9_8, kernel-rt-debug-core 5.14.0-687.31.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-64k 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-64k-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, kernel-rt-modules-core 5.14.0-427.158.1.el9_4, kernel-rt-debug-modules 5.14.0-427.158.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.117.1.el10_0, kernel-rt-64k 6.12.0-55.117.1.el10_0, kernel-rt-core 6.12.0-55.117.1.el10_0, kernel-rt-modules 6.12.0-55.117.1.el10_0, kernel-rt-64k-core 6.12.0-55.117.1.el10_0, kernel-rt-debug-core 6.12.0-55.117.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.152.1.el9_6, kernel-rt-64k 5.14.0-570.152.1.el9_6, kernel-rt-core 5.14.0-570.152.1.el9_6, kernel-rt-modules 5.14.0-570.152.1.el9_6, kernel-rt-64k-core 5.14.0-570.152.1.el9_6, kernel-rt-debug-core 5.14.0-570.152.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:91492
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.31.1.el9_8, kernel-rt-core 5.14.0-687.31.1.el9_8, kernel-rt-modules 5.14.0-687.31.1.el9_8, kernel-rt-debug-core 5.14.0-687.31.1.el9_8, kernel-rt-modules-core 5.14.0-687.31.1.el9_8, kernel-rt-debug-modules 5.14.0-687.31.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:47040
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.7.1.el10_2, kernel-rt-core 6.12.0-211.7.1.el10_2, kernel-rt-modules 6.12.0-211.7.1.el10_2, kernel-rt-debug-core 6.12.0-211.7.1.el10_2, kernel-rt-modules-core 6.12.0-211.7.1.el10_2, kernel-rt-debug-modules 6.12.0-211.7.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:18134
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-kvm 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.117.1.el10_0, kernel-rt-kvm 6.12.0-55.117.1.el10_0, kernel-rt-core 6.12.0-55.117.1.el10_0, kernel-rt-modules 6.12.0-55.117.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.117.1.el10_0, kernel-rt-debug-core 6.12.0-55.117.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.152.1.el9_6, kernel-rt-kvm 5.14.0-570.152.1.el9_6, kernel-rt-core 5.14.0-570.152.1.el9_6, kernel-rt-modules 5.14.0-570.152.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.152.1.el9_6, kernel-rt-debug-core 5.14.0-570.152.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:91492

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 d ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.