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NVD / CVE Program· CNA Linux

CVE-2025-39797: xfrm: Duplicate SPI Handling

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 29e9158f91f99057dbd35db5e8674d93b38549fe, 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38, 3d8090bb53424432fa788fe9a49e8ceca74f0544; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 29e9158f91f99057dbd35db5e8674d93b38549fe, 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38, 3d8090bb53424432fa788fe9a49e8ceca74f0544; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 12, 2025
Updated
Oct 30, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernelbefore 6.6.103
  • linux linux kernel6.7 and later · before 6.12.43
  • linux linux kernel6.13 and later · before 6.15.11
  • linux linux kernel6.16 and later · before 6.16.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before fb58962aa3b9359988c7b5b15a971fd9ad5b0ecdaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3d8090bb53424432fa788fe9a49e8ceca74f0544affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 29e9158f91f99057dbd35db5e8674d93b38549feaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 94f39804d891cffe4ce17737d295f3b195bc7299affected · git
    • before 2.6.12not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.103 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.7.1.el10_26.12.0-211.7.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39795Sep 12, 2025 · block: avoid possible overflow for chunk_sectors check in blk_stack_limits()
    22Monitor
  • ← EarlierCVE-2025-39796Sep 12, 2025 · net: lapbether: ignore ops-locked netdevs
    31Monitor
  • Later →CVE-2025-39798Sep 12, 2025 · NFS: Fix the setting of capabilities when automounting a new filesystem
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux29e9158f91f99057dbd35db5e8674d93b38549feVendor (CNA)
Linux Linux2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38Vendor (CNA)
Linux Linux3d8090bb53424432fa788fe9a49e8ceca74f0544Vendor (CNA)
Linux Linux94f39804d891cffe4ce17737d295f3b195bc7299Vendor (CNA)
Linux Linuxc67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47Vendor (CNA)
Linux Linuxfb58962aa3b9359988c7b5b15a971fd9ad5b0ecdVendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.31.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel6.12.0-211.7.1.el10_2 · AlmaLinux:10Package registry (OSV)

+39

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records