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Full vulnerability report · 2026
CVE-2025-59969High confidence

Junos OS Evolved: QFX5000 Series and PTX Series: An attacker sending crafted multicast packets will cause evo-aftmand / evo-pfemand to crash and restart

Juniper Networks · Junos OS Evolved

7.1HighCVSS 4.0
Recommended action
Within 7 days

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

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.18% 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 Juniper Networks Junos OS Evolved 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: Within 30 daysRemediation target: Within 180 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.

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-2025-209396

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 actionWithin 7 days

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

Patch available
01

What, why and how

A Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in the advanced forwarding toolkit (evo-aftmand/evo-pfemand) of Juniper Networks Junos OS Evolved on PTX Series or QFX5000 Series allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS).An attacker sending crafted multicast packets will cause line cards running evo-aftmand/evo-pfemand to crash and restart or non-line card devices to crash and restart. Continued receipt and processing of these packets will sustain the Denial of Service (DoS) condition. This issue affects Junos OS Evolved PTX Series: * All versions before 22.4R3-S8-EVO, * from 23.2 before 23.2R2-S5-EVO, * from 23.4 before 23.4R2-EVO, * from 24.2 before 24.2R2-EVO, * from 24.4 before 24.4R2-EVO. This issue affects Junos OS Evolved on QFX5000 Series: * 22.2-EVO version before 22.2R3-S7-EVO, * 22.4-EVO version before 22.4R3-S7-EVO, * 23.2-EVO versions before 23.2R2-S4-EVO, * 23.4-EVO versions before 23.4R2-S5-EVO, * 24.2-EVO versions before 24.2R2-S1-EVO, * 24.4-EVO versions before 24.4R1-S3-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved on QFX5000 Series versions before: 21.2R2-S1-EVO, 21.2R3-EVO, 21.3R2-EVO, 21.4R1-EVO, and 22.1R1-EVO.

What

A Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in the advanced forwarding toolkit (evo-aftmand/evo-pfemand) of Juniper Networks Junos OS Evolved on PTX Series or QFX5000 Series allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS).An attacker sending crafted multicast packets will cause line cards running evo-aftmand/evo-pfemand to crash and restart or non-line card devices to crash and restart. Continued receipt and processing of these packets will sustain the Denial of Service (DoS) condition. This issue affects Junos OS Evolved PTX Series: * All versions before 22.4R3-S8-EVO, * from 23.2 before 23.2R2-S5-EVO, * from 23.4 before 23.4R2-EVO, * from 24.2 before 24.2R2-EVO, * from 24.4 before 24.4R2-EVO. This issue affects Junos OS Evolved on QFX5000 Series: * 22.2-EVO version before 22.2R3-S7-EVO, * 22.4-EVO version before 22.4R3-S7-EVO, * 23.2-EVO versions before 23.2R2-S4-EVO, * 23.4-EVO versions before 23.4R2-S5-EVO, * 24.2-EVO versions before 24.2R2-S1-EVO, * 24.4-EVO versions before 24.4R1-S3-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved on QFX5000 Series versions before: 21.2R2-S1-EVO, 21.2R3-EVO, 21.3R2-EVO, 21.4R1-EVO, and 22.1R1-EVO.

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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

A Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in the advanced forwarding toolkit (evo-aftmand/evo-pfemand) of Juniper Networks Junos OS Evolved on PTX Series or QFX5000 Series allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS).An attacker sending crafted multicast packets will cause line cards running evo-aftmand/evo-pfemand to crash and restart or non-line card devices to crash and restart. Continued receipt and processing of these packets will sustain the Denial of Service (DoS) condition. This issue affects Junos OS Evolved PTX Series: * All versions before 22.4R3-S8-EVO, * from 23.2 before 23.2R2-S5-EVO, * from 23.4 before 23.4R2-EVO, * from 24.2 before 24.2R2-EVO, * from 24.4 before 24.4R2-EVO. This issue affects Junos OS Evolved on QFX5000 Series: * 22.2-EVO version before 22.2R3-S7-EVO, * 22.4-EVO version before 22.4R3-S7-EVO, * 23.2-EVO versions before 23.2R2-S4-EVO, * 23.4-EVO versions before 23.4R2-S5-EVO, * 24.2-EVO versions before 24.2R2-S1-EVO, * 24.4-EVO versions before 24.4R1-S3-EVO, 24.4R2-EVO. This issue does not affect Junos OS Evolved on QFX5000 Series versions before: 21.2R2-S1-EVO, 21.2R3-EVO, 21.3R2-EVO, 21.4R1-EVO, and 22.1R1-EVO.

Why

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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 → Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') → 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
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-120 ↗

CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow'). The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/V:C/RE:M/U:Amber

Common Vulnerability Scoring System 4.0: 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.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SALowSubsequent-system availability: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
UnauthenticatedDenial of serviceCWE-120
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-1022Juniper Patchday April 2026: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Juniper Apstra, Junos OS, Junos OS Evolved und Junos Space ausnutzen, um erweiterte Berechtigungen – sogar Root-Rechte – zu erlangen, beliebigen Code auszuführen – auch mit erweiterten Berechtigungen –, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, Cross-Site-Scripting-Angriffe durchzuführen oder Daten zu manipulieren.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-013454ジュニパーネットワークスのJunos OS Evolvedにおける古典的バッファオーバーフローの脆弱性

Juniper Networks Junos OS EvolvedのPTXシリーズおよびQFX5000シリーズの高度転送ツールキット（evo-aftmand/evo-pfemand）には、入力サイズのチェックを行わずにバッファコピーを実施する、いわゆる古典的なバッファオーバーフローの脆弱性が存在します。この脆弱性により、認証されていない隣接する攻撃者がサービス拒否（DoS）を引き起こす可能性があります。細工されたマルチキャストパケットを送信する攻撃者は、evo-aftmand/evo-pfemandを実行しているラインカードやラインカード以外のデバイスをクラッシュまたは再起動させることが可能です。これらのパケットを受信して処理し続けることで、DoS状態が持続します。この問題は、Junos OS Evolved PTXシリーズの以下のバージョンに影響します。22.4R3-S8-EVOより前のすべてのバージョン、23.2の23.2R2-S5-EVOより前のバージョン、23.4の23.4R2-EVOより前のバージョン、24.2の24.2R2-EVOより前のバージョン、および24.4の24.4R2-EVOより前のバージョンです。また、Junos OS EvolvedのQFX5000シリーズの以下のバージョンにも影響があります。22.2-EVOの22.2R3-S7-EVOより前、22.4-EVOの22.4R3-S7-EVOより前、23.2-EVOの23.2R2-S4-EVOより前、23.4-EVOの23.4R2-S5-EVOより前、24.2-EVOの24.2R2-S1-EVOより前、および24.4-EVOの24.4R1-S3-EVOおよび24.4R2-EVOです。なお、この問題はQFX5000シリーズのJunos OS Evolvedの21.2R2-S1-EVO、21.2R3-EVO、21.3R2-EVO、21.4R1-EVO、および22.1R1-EVOより前のバージョンには影響しません。

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
Junos OS Evolved: < 22.4R3-S8-EVO, 23.2 < 23.2R2-S5-EVO, 23.4 < 23.4R2-EVO, 24.2 < 24.2R2-EVO, 24.4 < 24.4R2-EVO, 22.2 < 22.2R3-S7-EVO, 22.4 < 22.4R3-S7-EVO, 23.2 < 23.2R2-S4-EVO, 23.4 < 23.4R2-S5-EVO, 24.2 < 24.2R2-S1-EVO, 24.4 < 24.4R1-S3-EVO, 24.4R2-EVO
Fixed
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 9 Apr 2026 · Last source change 10 Apr 2026, 18:15 UTC · CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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-2025-209396
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 ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: kb.juniper.net/JSA103159.
    Before
    vendor advisory: kb.juniper.net/JSA103159
    After
    remediation: kb.juniper.net/JSA103159 · vendor advisory: kb.juniper.net/JSA103159
    sirt@juniper.net ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 22.4R3-S8-EVO; 23.2 < 23.2R2-S5-EVO; 23.4 < 23.4R2-EVO; 24.2 < 24.2R2-EVO; 24.4 < 24.4R2-EVO; 22.2 < 22.2R3-S7-EVO; 22.4 < 22.4R3-S7-EVO; 23.2 < 23.2R2-S4-EVO · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Junos OS Evolved: < 22.4R3-S8-EVO, 23.2 < 23.2R2-S5-EVO, 23.4 < 23.4R2-EVO, 24.2 < 24.2R2-EVO, 24.4 < 24.4R2-EVO, 22.2 < 22.2R3-S7-EVO, 22.4 < 22.4R3-S7-EVO, 23.2 < 23.2R2-S4-EVO, 23.4 < 23.4R2-S5-EVO, 24.2 < 24.2R2-S1-EVO, 24.4 < 24.4R1-S3-EVO, 24.4R2-EVO · Fixed: The following software releases have been updated to resolve this specific issue:; For PTX Series: 22.4R3-S8-EVO, 23.2R2-S5-EVO, 23.4R2-EVO, 24.2R2-EVO, 24.4R2-EVO, 25.2R1-EVO, and all subsequent releases.; For QFX5000 Series: 22.2R3-S7-EVO, 22.4R3-S7-EVO, 23.2R2-S4-EVO, 23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO, 24.4R2-EVO, 25.2R1-EVO, and all subsequent releases.
    CNA ↗
  3. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    sirt@juniper.net ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2025-209396↗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-2025-59969 · cve.blacktree.nl