BlackTreeIndependent security intelligence

Full vulnerability report · 2026

CVE-2026-64413High confidence

netfilter: ebtables: zero chainstack array

Linux · Linux

7.0HighCVSS 3.1

Recommended action

Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available

Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

20 package states

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu release	Source package	Vendor state	Fixed version	Evidence
Ubuntu 24.04 LTSnoble · standard archive	`linux`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-aws`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-fde`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-azure-nvidia`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gcp`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gke`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-gkeop`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-ibm`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-lowlatency`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-lowlatency`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-nvidia-tegra`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oem-6.11`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-oracle`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-raspi-realtime`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-realtime`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-riscv`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026
Ubuntu 24.04 LTSnoble · standard archive	`linux-xilinx`	Affected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.	`Not published in this feed`	Canonical record ↗Source updated 10 Sept 2026

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current

SSA-019113 · CSAF 2.0 · revision 2 · interimSiemens ProductCERTSSA-019113: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.6

5 known affected

The vendor explicitly identifies these products as affected by this CVE.

SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.6
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.6
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.6
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= V3.1.6
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= V3.1.6

Summary: In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: zero chainstack array sashiko reports: looking at ebtables table translation, could a sparse cpu_possible_mask lead to an uninitialized pointer free? If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible, but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at CPU 2, the cleanup loop will blindly decrement and call vfree() on newinfo->chainstack[1]. Not a real-world bug, such allocation isn't expected to fail in the first place.
Remediation: Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current

ENISA EUVD identifier

EUVD-2026-48957

No EUVD known-exploited evidence

In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: zero chainstack array sashiko reports: looking at ebtables table translation, could a sparse cpu_possible_mask lead to an uninitialized pointer free? If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible, but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at CPU 2, the cleanup loop will blindly decrement and call vfree() on newinfo->chainstack[1]. Not a real-world bug, such allocation isn't expected to fail in the first place.

EUVD state: Present in the current official mapping
Known exploitation: Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score: 7.0 · CVSS 3.1
Advisory evidence: No linked advisory details stored yet

Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available

What, why and how

What

Why

The product uses or accesses a resource that has not been initialized.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

The product uses or accesses a resource that has not been initialized.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: local access → Use of Uninitialized Resource → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Local
Privileges required: Low: a basic authenticated account is required
User interaction: None
Attack complexity: High: exploitation depends on specific conditions
Security boundary: Unchanged: impact remains within the vulnerable component's security authority
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-908 ↗
CWE-908: Use of Uninitialized Resource. The product uses or accesses a resource that has not been initialized.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land: The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.

CWE-908

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-48957Official EUVD mapping

Official EUVD record

BSI · German · WID-SEC-W-2026-2527Linux Kernel: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um nicht näher spezifizierte Angriffe durchzuführen, dazu können DoS-Angriffe, die Offenlegung von Informationen, die Beschädigung des Speichers oder die Umgehung von Sicherheitsmaßnahmen gehören.

Official advisory

CERT-FR · French · CERTFR-2026-AVI-1031Multiples vulnérabilités dans le noyau Linux de Debian LTS

d?id=CVE-2026-64403 Référence CVE CVE-2026-64404 https://www.cve.org/CVERecord?id=CVE-2026-64404 Référence CVE CVE-2026-64405 https://www.cve.org/CVERecord?id=CVE-2026-64405 Référence CVE CVE-2026-64406 https://www.cve.org/CVERecord?id=CVE-2026-64406 Référence CVE CVE-2026-64407 https://www.cve.org/CVERecord?id=CVE-2026-64407 Référence CVE CVE-2026-64408 https://www.cve.org/CVERecord?id=CVE-2026-64408 Référence CVE CVE-2026-64409 https://www.cve.org/CVERecord?id=CVE-2026-64409 Référence CVE CVE-2026-64411 https://www.cve.org/CVERecord?id=CVE-2026-64411 Référence CVE CVE-2026-64412 https://www.cve.org/CVERecord?id=CVE-2026-64412 Référence CVE CVE-2026-64413 https://www.cve.org/CVERecord?id=CVE-2026-64413 Référence CVE CVE-2026-64414 https://www.cve.org/CVERecord?id=CVE-2026-64414 Référence CVE CVE-2026-64415 https://www.cve.org/CVERecord?id=CVE-2026-64415 Référence CVE CVE-2026-64416 https://www.cve.org/CVERecord?id=CVE-2026-64416 Référence CVE CVE-2026-64417 https://www.cve.org/CVERecord?id=CVE-2026-64417 Référence CVE CVE-2026-64418 https://www.cve.org/CVERecord?id=CVE-2026-64418 Référence CVE CVE-2026-64419 https://www.cve.org/CVERecord?id=CVE-2026-64419 Référence CVE CVE-2026-64420 https://www.cve.org/CVERecord?id=CVE-2026-64420 Référence CVE CVE-2026-64421 https://www.cve.org/CVERecord?id=

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0982Multiples vulnérabilités dans le noyau Linux de Debian LTS

d?id=CVE-2026-64398 Référence CVE CVE-2026-64399 https://www.cve.org/CVERecord?id=CVE-2026-64399 Référence CVE CVE-2026-64401 https://www.cve.org/CVERecord?id=CVE-2026-64401 Référence CVE CVE-2026-64403 https://www.cve.org/CVERecord?id=CVE-2026-64403 Référence CVE CVE-2026-64406 https://www.cve.org/CVERecord?id=CVE-2026-64406 Référence CVE CVE-2026-64408 https://www.cve.org/CVERecord?id=CVE-2026-64408 Référence CVE CVE-2026-64409 https://www.cve.org/CVERecord?id=CVE-2026-64409 Référence CVE CVE-2026-64411 https://www.cve.org/CVERecord?id=CVE-2026-64411 Référence CVE CVE-2026-64412 https://www.cve.org/CVERecord?id=CVE-2026-64412 Référence CVE CVE-2026-64413 https://www.cve.org/CVERecord?id=CVE-2026-64413 Référence CVE CVE-2026-64417 https://www.cve.org/CVERecord?id=CVE-2026-64417 Référence CVE CVE-2026-64419 https://www.cve.org/CVERecord?id=CVE-2026-64419 Référence CVE CVE-2026-64420 https://www.cve.org/CVERecord?id=CVE-2026-64420 Référence CVE CVE-2026-64422 https://www.cve.org/CVERecord?id=CVE-2026-64422 Référence CVE CVE-2026-64423 https://www.cve.org/CVERecord?id=CVE-2026-64423 Référence CVE CVE-2026-64425 https://www.cve.org/CVERecord?id=CVE-2026-64425 Référence CVE CVE-2026-64428 https://www.cve.org/CVERecord?id=CVE-2026-64428 Référence CVE CVE-2026-64429 https://www.cve.org/CVERecord?id=

Official advisory

CERT-FR · French · CERTFR-2026-AVI-0981Multiples vulnérabilités dans le noyau Linux de Debian

d?id=CVE-2026-64361 Référence CVE CVE-2026-64363 https://www.cve.org/CVERecord?id=CVE-2026-64363 Référence CVE CVE-2026-64364 https://www.cve.org/CVERecord?id=CVE-2026-64364 Référence CVE CVE-2026-64369 https://www.cve.org/CVERecord?id=CVE-2026-64369 Référence CVE CVE-2026-64371 https://www.cve.org/CVERecord?id=CVE-2026-64371 Référence CVE CVE-2026-64375 https://www.cve.org/CVERecord?id=CVE-2026-64375 Référence CVE CVE-2026-64390 https://www.cve.org/CVERecord?id=CVE-2026-64390 Référence CVE CVE-2026-64401 https://www.cve.org/CVERecord?id=CVE-2026-64401 Référence CVE CVE-2026-64405 https://www.cve.org/CVERecord?id=CVE-2026-64405 Référence CVE CVE-2026-64413 https://www.cve.org/CVERecord?id=CVE-2026-64413 Référence CVE CVE-2026-64416 https://www.cve.org/CVERecord?id=CVE-2026-64416 Référence CVE CVE-2026-64421 https://www.cve.org/CVERecord?id=CVE-2026-64421 Référence CVE CVE-2026-64428 https://www.cve.org/CVERecord?id=CVE-2026-64428 Référence CVE CVE-2026-64434 https://www.cve.org/CVERecord?id=CVE-2026-64434 Référence CVE CVE-2026-64438 https://www.cve.org/CVERecord?id=CVE-2026-64438 Référence CVE CVE-2026-64441 https://www.cve.org/CVERecord?id=CVE-2026-64441 Référence CVE CVE-2026-64461 https://www.cve.org/CVERecord?id=CVE-2026-64461 Référence CVE CVE-2026-64462 https://www.cve.org/CVERecord?id=

Official advisory

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.6; SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.6; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.6; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= V3.1.6; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= V3.1.6
Fixed: < 2.6.12; 5.10.261 ≤ 5.10.*; 5.15.212 ≤ 5.15.*; 6.1.178 ≤ 6.1.*; 6.6.145 ≤ 6.6.*; 6.12.97 ≤ 6.12.*; 6.18.39 ≤ 6.18.*; 7.1.4 ≤ 7.1.*
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: Limit access to the interactive shell of the additional GNU/Linux subssytem to trusted personnel only.

Evidence and provenance

Published 25 Jul 2026 · Last source change 8 Sept 2026, 08:50 UTC · CWE-908 · Use of Uninitialized Resource

CVE recordCVE.org · 5.2

CVSS sourceCNA

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-08-14

European sourceENISA EUVD · EUVD-2026-48957

Product sourceVendor CSAF · Siemens ProductCERT

Remediation sourceVendor CSAF · Siemens ProductCERT

CWE sourceNIST NVD

NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

17 Aug 2026, 04:55 UTC
Vendor guidanceAuthoritative vendor guidance changed from authoritative remediation link to authoritative remediation link · patch.
Before
authoritative remediation link
After
authoritative remediation link · patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67 ↗

2026-07-25CVE published

2026-09-08Fixed release or patch reference recorded

ENISA EUVD · EUVD-2026-48957↗Vendor CSAF · Siemens ProductCERT↗CVE authority or vendor reference↗Patch or update reference↗Patch or update reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

netfilter: ebtables: zero chainstack array

National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

EUVD-2026-48957

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.