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NVD / CVE Program· CNA Linux

CVE-2025-39702: ipv6: sr: Fix MAC comparison to be constant-time

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.43% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 3b348c9c8d2ca2c67559ffd0e258ae7e1107d4f0, 3ddd55cf19ed6cc62def5e3af10c2a9df1b861c3, 86b6d34717fe0570afce07ee79b8eeb40341f831; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 9.8, NVD 7.0.

Low priority for now. Upgrade to Linux Linux 3b348c9c8d2ca2c67559ffd0e258ae7e1107d4f0, 3ddd55cf19ed6cc62def5e3af10c2a9df1b861c3, 86b6d34717fe0570afce07ee79b8eeb40341f831; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 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: ipv6: sr: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.

HighCVSS 7.0 · v3.1—No exploit Fix available
Published
Sep 5, 2025
Updated
Oct 19, 2026
EPSS
0.4% · 37th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.0
CNA · Linux
9.8
2.8 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-39702

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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
debiandebian linux

Affected versions

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

  • debian debian linux11.0
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel4.10 and later · before 5.15.190
  • linux linux kernel6.13 and later · before 6.16.4
  • linux linux kernel6.7 and later · before 6.12.44
  • linux linux kernel6.17

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

    • 4.10affected
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before ff55a452d56490047f5233cc48c5d933f8586884affected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before 3b348c9c8d2ca2c67559ffd0e258ae7e1107d4f0affected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before 86b6d34717fe0570afce07ee79b8eeb40341f831affected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before 3ddd55cf19ed6cc62def5e3af10c2a9df1b861c3affected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before b3967c493799e63f648e9c7b6cb063aa2aed04e7affected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before f7878d47560d61e3f370aca3cebb8f42a55b990aaffected · git
    • bf355b8d2c30a289232042cacc1cfaea4923936c and later · before a458b2902115b26a25d67393b12ddd57d1216aaaaffected · git
    • before 4.10not affected · semver
    • 5.10.249 and later · up to and including 5.10.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-55.42.1.el10_06.12.0-55.42.1.el10_0
AlmaLinux:10kernel-docbefore 6.12.0-55.42.1.el10_06.12.0-55.42.1.el10_0
AlmaLinux:9kernelbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64kbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debugbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-develbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-devel-matchedbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-modulesbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-modules-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-debug-modules-extrabefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-develbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-devel-matchedbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-modulesbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-modules-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-64k-modules-extrabefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-abi-stablelistsbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-cross-headersbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-debugbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-debug-corebefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-debug-develbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6
AlmaLinux:9kernel-debug-devel-matchedbefore 5.14.0-570.60.1.el9_65.14.0-570.60.1.el9_6

+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-2025-39700Sep 5, 2025 · mm/damon/ops-common: ignore migration request to invalid nodes
    22Monitor
  • ← EarlierCVE-2025-39701Sep 5, 2025 · ACPI: pfr_update: Fix the driver update version check
    31Monitor
  • Later →CVE-2025-39703Sep 5, 2025 · net, hsr: reject HSR frame if skb can't hold tag
    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 Linux3b348c9c8d2ca2c67559ffd0e258ae7e1107d4f0Vendor (CNA)
Linux Linux3ddd55cf19ed6cc62def5e3af10c2a9df1b861c3Vendor (CNA)
Linux Linux86b6d34717fe0570afce07ee79b8eeb40341f831Vendor (CNA)
Linux Linuxa458b2902115b26a25d67393b12ddd57d1216aaaVendor (CNA)
Linux Linuxb3967c493799e63f648e9c7b6cb063aa2aed04e7Vendor (CNA)
Linux Linuxf7878d47560d61e3f370aca3cebb8f42a55b990aVendor (CNA)
Linux Linuxff55a452d56490047f5233cc48c5d933f8586884Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-570.60.1.el9_6 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)
opensuse:dtb-aarch646.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-64kb6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-default-base6.12.0-160000.6.1.160000.2.4 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-docs6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-kvmsmall6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-build6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:kernel-obs-qa6.12.0-160000.7.1 · openSUSE:Leap 16.0Package registry (OSV)

+27

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.

  • CVE-2021-47226472 days apartx86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer
    28Monitor
  • CVE-2024-50102304 days apartx86: fix user address masking non-canonical speculation issue
    22Monitor
  • CVE-2024-47678319 days aparticmp: change the order of rate limits
    22Monitor
  • CVE-2022-48730442 days apartdma-buf: heaps: Fix potential spectre v1 gadget
    22Monitor

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.
  • Special conditions such as timing or configuration are required.

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
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-203 · Observable Discrepancy

CVSS vector

CVSS:3.1/AV:L/AC:H/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.

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records