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Full vulnerability report · 2026
CVE-2026-49424High confidence

Kernel stack disclosure in Linux compatibility layer

FreeBSD · FreeBSD

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Low, lowered one band.downgradedsince 26 Aug 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • Exploitation requires an existing local or physical foothold with privileges.
  • EPSS is 0.15% for the current model date.

Compensating controls

  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs FreeBSD FreeBSD and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: No default targetRemediation target: Normal maintenance

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

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

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

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-2026-62345

No EUVD known-exploited evidence

The Linux waitid() implementation translates a FreeBSD siginfo_t struct into a stack-declared Linux siginfo_t. It did not first zero the stack struct. An unprivileged user may observe 104 bytes of uninitialized kernel stack data, which may contain sensitive information.

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
5.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
01

What, why and how

The Linux waitid() implementation translates a FreeBSD siginfo_t struct into a stack-declared Linux siginfo_t. It did not first zero the stack struct. An unprivileged user may observe 104 bytes of uninitialized kernel stack data, which may contain sensitive information.

What

The Linux waitid() implementation translates a FreeBSD siginfo_t struct into a stack-declared Linux siginfo_t. It did not first zero the stack struct. An unprivileged user may observe 104 bytes of uninitialized kernel stack data, which may contain sensitive information.

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 obtain information outside the intended access boundary.

What

The Linux waitid() implementation translates a FreeBSD siginfo_t struct into a stack-declared Linux siginfo_t. It did not first zero the stack struct. An unprivileged user may observe 104 bytes of uninitialized kernel stack data, which may contain sensitive information.

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 obtain information outside the intended access boundary.

02

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 → obtain information outside the intended access boundary
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
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:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.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.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
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
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-62345Official EUVD mapping

The Linux waitid() implementation translates a FreeBSD siginfo_t struct into a stack-declared Linux siginfo_t. It did not first zero the stack struct. An unprivileged user may observe 104 bytes of uninitialized kernel stack data, which may contain sensitive information.

Official EUVD record ↗
BSI · German · WID-SEC-2026-2165FreeBSD Project FreeBSD OS: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in FreeBSD Project FreeBSD OS ausnutzen, um seine Privilegien zu erhöhen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Denial of Service Angriff durchzuführen, und um beliebigen Programmcode auszuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260826Security Bulletin 26 Aug 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 26 Aug 2026, published on 26 August 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0830Vulnérabilité dans FreeBSD

Une vulnérabilité a été découverte dans FreeBSD. Elle permet à un attaquant de provoquer une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-031068FreeBSDにおける初期化されていないリソースの使用に関する脆弱性

Linuxのwaitid()の実装では、FreeBSDのsiginfo_t構造体をスタック上に宣言されたLinuxのsiginfo_tに変換します。この際、スタック上の構造体を最初にゼロクリアしていませんでした。そのため、権限のないユーザーが機密情報を含む可能性のある104バイトの初期化されていないカーネルスタックデータを観察できる恐れがあります。

Official advisory ↗
03

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.
Fix not verified
Affected
FreeBSD: 15.0-RELEASE < p11, 14.4-RELEASE < p7, 14.3-RELEASE < p16
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 19 Aug 2026 · Last source change 26 Aug 2026, 17:52 UTC · CWE-908 · Use of Uninitialized Resource

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-62345
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD awaiting enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. SeveritySeverity changed from Unknown to Medium.
    Before
    Unknown
    After
    Medium
    CISA ADP ↗
  2. CVSS scoreCVSS score changed from not recorded to 5.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).
    Before
    not recorded
    After
    5.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
    CISA ADP ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-62345↗CVE authority or vendor 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.
Free version - for non-commercial use only.CVE-2026-49424 · cve.blacktree.nl