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NVD / CVE Program· CNA Linux

CVE-2026-31428: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.13% (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 21d8efda029948d3666b0db5afcc0d36c0984aae, 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7, 7eff72968161fb8ddb26113344de3b92fb7d7ef5; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2.

Low priority for now. Upgrade to Linux Linux 21d8efda029948d3666b0db5afcc0d36c0984aae, 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7, 7eff72968161fb8ddb26113344de3b92fb7d7ef5; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2 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: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD __build_packet_message() manually constructs the NFULA_PAYLOAD netlink attribute using skb_put() and skb_copy_bits(), bypassing the standard nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes are allocated (including NLA alignment padding), only data_len bytes of actual packet data are copied. The trailing nla_padlen(data_len) bytes (1-3 when data_len is not 4-byte aligned) are never initialized, leaking stale heap contents to userspace via the NFLOG netlink socket. Replace the manual attribute construction with nla_reserve(), which handles the tailroom check, header setup, and padding zeroing via __nla_reserve(). The subsequent skb_copy_bits() fills in the payload data on top of the properly initialized attribute.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 13, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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

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  • 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.

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 kernel2.6.24 and later · before 5.10.253
  • linux linux kernel5.11 and later · before 5.15.203
  • linux linux kernel5.16 and later · before 6.1.168
  • linux linux kernel6.2 and later · before 6.6.131
  • linux linux kernel6.7 and later · before 6.12.80
  • linux linux kernel6.13 and later · before 6.18.21
  • linux linux kernel6.19 and later · before 6.19.11
  • linux linux kernel7.0

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

    • 2.6.24affected
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before 7f3e5d72455936f42709116fabeca3bb216cda62affected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before 21d8efda029948d3666b0db5afcc0d36c0984aaeaffected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before fc961dd7272b5e4a462999635e44a4770d7f2482affected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before a8365d1064ded323797c5e28e91070c52f44b76caffected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before a2f6ff3444b663d6cfa63eadd61327a18592885aaffected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before c9f6c51d36482805ac3ffadb9663fe775a13e926affected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before 7eff72968161fb8ddb26113344de3b92fb7d7ef5affected · git
    • df6fb868d6118686805c2fa566e213a8f31c8e4f and later · before 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7affected · git
    • before 2.6.24not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.11-16.19.11-1

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-2026-31426Apr 13, 2026 · ACPI: EC: clean up handlers on probe failure in acpi_ec_setup()
    28Monitor
  • ← EarlierCVE-2026-31427Apr 13, 2026 · netfilter: nf_conntrack_sip: fix use of uninitialized rtp_addr in process_sdp
    22Monitor
  • Later →CVE-2026-31429Apr 20, 2026 · net: skb: fix cross-cache free of KFENCE-allocated skb head
    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 Linux21d8efda029948d3666b0db5afcc0d36c0984aaeVendor (CNA)
Linux Linux52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7Vendor (CNA)
Linux Linux7eff72968161fb8ddb26113344de3b92fb7d7ef5Vendor (CNA)
Linux Linux7f3e5d72455936f42709116fabeca3bb216cda62Vendor (CNA)
Linux Linuxa2f6ff3444b663d6cfa63eadd61327a18592885aVendor (CNA)
Linux Linuxa8365d1064ded323797c5e28e91070c52f44b76cVendor (CNA)
Linux Linuxc9f6c51d36482805ac3ffadb9663fe775a13e926Vendor (CNA)
Linux Linuxfc961dd7272b5e4a462999635e44a4770d7f2482Vendor (CNA)
azl3 kernel 6.6.130.1-3 on Azure Linux 3.06.6.134.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.170-1 · 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.

  • CVE-2024-50302510 days apartHID: core: zero-initialize the report bufferKEV
    52Plan
  • CVE-2026-5298972 days apartnvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers
    39Monitor
  • CVE-2026-5322573 days apartsctp: fix uninit-value in __sctp_rcv_asconf_lookup()
    36Monitor
  • CVE-2024-47685539 days apartnetfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()
    36Monitor
  • CVE-2026-5317073 days apartaccel/ethosu: reject DMA commands with uninitialized length
    35Monitor
  • CVE-2026-4313923 days apartxfrm6: fix uninitialized saddr in xfrm6_get_saddr()
    34Monitor

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

Weakness class (CWE)

CWE-908 · Use of Uninitialized Resource

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 (10 more)

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

All records