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Full vulnerability report · 2026
CVE-2026-20230High confidence

Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) Vulnerability

Cisco · Unified Communications Manager

Official source article: Cisco CISCO-SA-CUCM-SSRF-CXPNHCW ↗. Check the applicable product and release in the original source.

8.6HighCVSS 3.1
Recommended action
Mitigate now

CISA confirms exploitation in the wild and lists 2026-06-28 as the remediation due date.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 25 Jun 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 88.20% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Cisco Unified Communications Manager 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: Within 3 daysRemediation target: Within 90 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-2026-34137

CISA KEV mirrored by ENISA

A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery (SSRF) attacks through an affected device. This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root. Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root. Note: To exploit this vulnerability, the WebDialer service must be enabled. WebDialer is disabled by default.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 25 Jun 2026. Evidence sources: cisa_kev.
ENISA score
8.6 · CVSS 3.1
Advisory evidence
2 linked advisory records
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0174Kwetsbaarheid verholpen in Cisco Unified Communications Manager
Recommended actionMitigate now

CISA confirms exploitation in the wild and lists 2026-06-28 as the remediation due date.

Mitigation available
01

What, why and how

Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) contain a server-side request forgery (SSRF) Vulnerability that could allow an unauthenticated, remote attacker to write files to the underlying operating system that could be used later to elevate to root.

What

Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) contain a server-side request forgery (SSRF) Vulnerability that could allow an unauthenticated, remote attacker to write files to the underlying operating system that could be used later to elevate to root.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may gain additional privileges.

What

Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) contain a server-side request forgery (SSRF) Vulnerability that could allow an unauthenticated, remote attacker to write files to the underlying operating system that could be used later to elevate to root.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may gain additional privileges.

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.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-06-25.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Server-Side Request Forgery (SSRF) → gain additional privileges
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-918 ↗

CWE-918: Server-Side Request Forgery (SSRF). The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

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

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

AVNetworkAttack vector: The vulnerable component can be reached over a 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.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.ANoneAvailability impact: No direct loss is represented by this metric.
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.
NetworkUnauthenticatedPrivilege escalationCWE-918CISA KEVPublic exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-34137Known-exploited evidence recorded

A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery (SSRF) attacks through an affected device. This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root. Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root. Note: To exploit this vulnerability, the WebDialer service must be enabled. WebDialer is disabled by default.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1801Cisco Unified Communications Manager (CUCM): Schwachstelle ermöglicht Manipulation von Dateien

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Cisco Unified Communications Manager (CUCM) ausnutzen, um Dateien zu manipulieren und dadurch potenziell root Rechte zu erlangen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-547Cisco security advisory (AV26-547) – Update 1

On June 3, 2026, Cisco published security advisories to address vulnerabilities in multiple products. Included was a critical update for the following: Cisco has indicated that a proof-of-concept exploit code is available for CVE-2026-20230.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260610Security Bulletin 10 Jun 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Jun 2026, published on 10 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0689Vulnérabilité dans les produits Cisco

Une vulnérabilité a été découverte dans les produits Cisco. Elle permet à un attaquant de provoquer une falsification de requêtes côté serveur (SSRF).

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-021508シスコシステムズのCisco Unified Communications Managerにおけるサーバサイドのリクエストフォージェリの脆弱性

Cisco Unified Communications Manager（Unified CM）および Cisco Unified Communications Manager Session Management Edition（Unified CM SME）には脆弱性が存在し、認証されていないリモート攻撃者が影響を受けるデバイスを通じてサーバーサイドリクエストフォージェリ（SSRF）攻撃を実行できる可能性があります。この脆弱性は特定のHTTPリクエストに対する入力検証の不備が原因です。攻撃者は細工されたHTTPリクエストを影響を受けるデバイスに送信することで、この脆弱性を悪用できます。悪用に成功すると、攻撃者は基盤となるオペレーティングシステムにファイルを書き込み、その後にroot権限へ昇格するために使用する可能性があります。注：Ciscoは本セキュリティアドバイザリに対して、影響度評価（SIR）のスコアを高（High）ではなく重大（Critical）に割り当てています。これは、この脆弱性の悪用により攻撃者がroot権限に昇格できる可能性があるためです。注：この脆弱性を悪用するには、WebDialerサービスを有効にしている必要があります。なお、WebDialerはデフォルトで無効となっています。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6858美 CISA 발표 주요 Exploit 정보공유(Update. 2026-06-25)

Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) Vulnerability

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0174Kwetsbaarheid verholpen in Cisco Unified Communications Manager

Een kwaadwillende kan de kwetsbaarheid misbruiken om een Server-Side Request Forgery (SSRF)-aanval uit te voeren. Succesvol misbruik kan leiden tot het injecteren van bestanden en/of scripts, waarmee de kwaadwillende zichzelf root-rechten kan verschaffen. Voor succesvol misbruik moet de WebDialer service actief zijn. Deze is standaard niet actief en moet bewust zijn geactiveerd door de beheerder. Door deze beperking is grootschalig misbruik minder waarschijnlijk. Cisco meldt bekend te zijn met Proof-of-Concept-code (PoC) die de kwetsbaarheid aantoont. Vooralsnog is (nog) geen publieke PoC of exploit bekend en er is nog geen actief misbruik waargenomen.

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.
Mitigation available
Affected
Cisco Unified Communications Manager: 14, 14SU1, 14SU2, 14SU3, 15, 15SU1, 14SU4, 14SU4a, 15SU1a, 15SU2, 15.0.1.13010-1, 15.0.1.13011-1, 15.0.1.13012-1, 15.0.1.13013-1, 15.0.1.13014-1, 15.0.1.13015-1, 15.0.1.13016-1, 15.0.1.13017-1, 15SU3a, 14SU5, 15SU4, 15SU4a
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
The Cyber Centre encourages users and administrators to review the provided web links and apply the necessary updates.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles1 stored document

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

04

Evidence and provenance

Published 3 Jun 2026 · Last source change 1 Jul 2026, 16:28 UTC · CWE-918 · Server-Side Request Forgery (SSRF)

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-2026-34137
Product sourceCISA KEV
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. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: cyber.gc.ca/cisco-security-advisory-av26-547.
    Before
    remediation: cyber.gc.ca/cisco-security-advisory-av26-547 · vendor advisory: sec.cloudapps.cisco.com/cisco-sa-cucm-ssrf-cXPnHcW
    After
    vendor advisory: sec.cloudapps.cisco.com/cisco-sa-cucm-ssrf-cXPnHcW
    psirt@cisco.com ↗
  3. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    psirt@cisco.com ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    14; 14SU1; 14SU2; 14SU3; 15; 15SU1; 14SU4; 14SU4a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Cisco Unified Communications Manager: 14, 14SU1, 14SU2, 14SU3, 15, 15SU1, 14SU4, 14SU4a, 15SU1a, 15SU2, 15.0.1.13010-1, 15.0.1.13011-1, 15.0.1.13012-1, 15.0.1.13013-1, 15.0.1.13014-1, 15.0.1.13015-1, 15.0.1.13016-1, 15.0.1.13017-1, 15SU3a, 14SU5, 15SU4, 15SU4a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Canadian Centre for Cyber Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Remediation guidance recorded
ENISA EUVD · EUVD-2026-34137↗Canadian Centre for Cyber Security remediation guidance↗CISA KEV record↗CVE authority or vendor reference · Cisco CISCO-SA-CUCM-SSRF-CXPNHCW↗Public exploit 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-2026-20230 · cve.blacktree.nl