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NVD / CVE Program· CNA Linux

CVE-2025-40279: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 218b67c8c8246d47a2a7910eae80abe4861fe2b7, 25837889ec062f2b7618142cd80253dff3da5343, 31e4aa93e2e5b5647fc235b0f6ee329646878f9e; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1.

Low priority for now. Upgrade to Linux Linux 218b67c8c8246d47a2a7910eae80abe4861fe2b7, 25837889ec062f2b7618142cd80253dff3da5343, 31e4aa93e2e5b5647fc235b0f6ee329646878f9e; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1 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: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak In tcf_connmark_dump(), the variable 'opt' was partially initialized using a designatied initializer. While the padding bytes are reamined uninitialized. nla_put() copies the entire structure into a netlink message, these uninitialized bytes leaked to userspace. Initialize the structure with memset before assigning its fields to ensure all members and padding are cleared prior to beign copied.

—No exploit Fix available
Published
Dec 6, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
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  • 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.

—

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

    • 4.0affected
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 218b67c8c8246d47a2a7910eae80abe4861fe2b7affected · git
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 73cc56c608c209d3d666cc571293b090a471da70affected · git
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 31e4aa93e2e5b5647fc235b0f6ee329646878f9eaffected · git
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 51cb05d4fd632596816ba44e882e84db9fb28a7eaffected · git
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 25837889ec062f2b7618142cd80253dff3da5343affected · git
    • 22a5dc0e5e3e8fef804230cd73ed7b0afd4c7bae and later · before 62b656e43eaeae445a39cd8021a4f47065af4389affected · git
    • before 4.0not affected · semver
    • 5.15.197 and later · up to and including 5.15.*not affected · semver
    • 6.1.159 and later · up to and including 6.1.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.159-16.1.159-1
Debian:13linuxbefore 6.12.63-16.12.63-1
Debian:14linuxbefore 6.17.9-16.17.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40277Dec 6, 2025 · drm/vmwgfx: Validate command header size against SVGA_CMD_MAX_DATASIZE
    31Monitor
  • ← EarlierCVE-2025-40278Dec 6, 2025 · net: sched: act_ife: initialize struct tc_ife to fix KMSAN kernel-infoleak
    0Monitor
  • Later →CVE-2025-40281Dec 6, 2025 · sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto
    0Monitor

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 Linux218b67c8c8246d47a2a7910eae80abe4861fe2b7Vendor (CNA)
Linux Linux25837889ec062f2b7618142cd80253dff3da5343Vendor (CNA)
Linux Linux31e4aa93e2e5b5647fc235b0f6ee329646878f9eVendor (CNA)
Linux Linux51cb05d4fd632596816ba44e882e84db9fb28a7eVendor (CNA)
Linux Linux62b656e43eaeae445a39cd8021a4f47065af4389Vendor (CNA)
Linux Linux73cc56c608c209d3d666cc571293b090a471da70Vendor (CNA)
azl3 kernel 6.6.112.1-2 on Azure Linux 3.06.6.117.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.159-1 · Debian:12Package registry (OSV)

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

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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✗ → ✓

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References

Show all references (5 more)

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

All records