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Full vulnerability report · 2026
CVE-2026-58374High confidence

w1.fi hostapd — Off-by-one Error

w1.fi · hostapd

6.5MediumCVSS 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.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.47% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • 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 w1.fi hostapd and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  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: As exposure requiresRemediation target: Within 365 days

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.

Distribution package intelligence

Release-specific package status

Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

4 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.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcewpaNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian bookwormbookworm · sourcewpaNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian forkyforky · sourcewpaNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
Debian sidsid · sourcewpaNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 5 Oct 2026
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-2026-40306

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
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.

Patch available
01

What, why and how

In hostapd before 2.12, a missing bounds check in AP-mode Wi-Fi 7 (IEEE 802.11be) Multi-Link Operation (MLO) association request processing allows an unauthenticated attacker within wireless range to send a crafted management frame containing a malformed Multi-Link Element or Per-STA Profile subelement. In hostapd_process_ml_assoc_req() in src/ap/ieee802_11_eht.c, the received link_id field can be parsed as value 15, but the corresponding links[] storage only has valid entries for lower link IDs (0 through 14). This causes an out-of-bounds write / small memory corruption during association processing before the 4-way handshake. The attack does not require network credentials, prior authentication, or user interaction. The confirmed practical impact is denial of service through hostapd process termination. This affects hostapd v2.11 and newer development snapshots before v2.12 when built with CONFIG_IEEE80211BE enabled. The issue is fixed in hostapd v2.12 and the upstream 2026-1 fixes.

What

In hostapd before 2.12, a missing bounds check in AP-mode Wi-Fi 7 (IEEE 802.11be) Multi-Link Operation (MLO) association request processing allows an unauthenticated attacker within wireless range to send a crafted management frame containing a malformed Multi-Link Element or Per-STA Profile subelement. In hostapd_process_ml_assoc_req() in src/ap/ieee802_11_eht.c, the received link_id field can be parsed as value 15, but the corresponding links[] storage only has valid entries for lower link IDs (0 through 14). This causes an out-of-bounds write / small memory corruption during association processing before the 4-way handshake. The attack does not require network credentials, prior authentication, or user interaction. The confirmed practical impact is denial of service through hostapd process termination. This affects hostapd v2.11 and newer development snapshots before v2.12 when built with CONFIG_IEEE80211BE enabled. The issue is fixed in hostapd v2.12 and the upstream 2026-1 fixes.

Why

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

In hostapd before 2.12, a missing bounds check in AP-mode Wi-Fi 7 (IEEE 802.11be) Multi-Link Operation (MLO) association request processing allows an unauthenticated attacker within wireless range to send a crafted management frame containing a malformed Multi-Link Element or Per-STA Profile subelement. In hostapd_process_ml_assoc_req() in src/ap/ieee802_11_eht.c, the received link_id field can be parsed as value 15, but the corresponding links[] storage only has valid entries for lower link IDs (0 through 14). This causes an out-of-bounds write / small memory corruption during association processing before the 4-way handshake. The attack does not require network credentials, prior authentication, or user interaction. The confirmed practical impact is denial of service through hostapd process termination. This affects hostapd v2.11 and newer development snapshots before v2.12 when built with CONFIG_IEEE80211BE enabled. The issue is fixed in hostapd v2.12 and the upstream 2026-1 fixes.

Why

A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

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
an adjacent network → Off-by-one Error → disrupt the affected service
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
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-193 ↗

CWE-193: Off-by-one Error. A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
UnauthenticatedDenial of serviceCWE-193
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-2154hostapd: Schwachstelle ermöglicht Denial of Service

Ein Angreifer aus einem angrenzenden Netzwerk kann eine Schwachstelle in hostapd ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260701Security Bulletin 1 July 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 1 July 2026, published on 1 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-021989w1.fiのhostapdにおける境界条件の判定に関する脆弱性

hostapd 2.12より前のバージョンにおいて、APモードのWi-Fi 7 (IEEE 802.11be) マルチリンクオペレーション(MLO)関連のアソシエーション要求処理に境界チェックが欠如しており、無線範囲内の認証されていない攻撃者が悪意のあるマルチリンク要素またはPer-STAプロファイルサブエレメントを含む細工された管理フレームを送信できる脆弱性があります。src/ap/ieee802_11_eht.cのhostapd_process_ml_assoc_req()関数では、受信したlink_idフィールドが値15として解析される可能性がありますが、対応するlinks[]配列は0から14までの下位リンクIDの有効なエントリのみを保持しています。これにより、4ウェイハンドシェイク前のアソシエーション処理中に境界外書き込みおよび小規模なメモリ破損が発生します。この攻撃にはネットワーク資格情報や事前認証、ユーザーの操作は不要です。実際の影響として、hostapdプロセスの終了を引き起こすサービス拒否が確認されています。この脆弱性はCONFIG_IEEE80211BEが有効な状態でビルドされたhostapd v2.11およびv2.12より前の開発スナップショットに影響します。問題はhostapd v2.12およびupstream 2026-1の修正で解決されています。

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.
Patch available
Affected
hostapd: < 2.12
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 30 Jun 2026 · Last source change 30 Jun 2026, 13:38 UTC · CWE-193 · Off-by-one Error

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-2026-40306
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

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

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
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-2026-58374 · cve.blacktree.nl