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Full vulnerability report · 2026
CVE-2026-20045High confidence

Cisco Unified Communications Products Code Injection Vulnerability

Cisco · Unified Communications Manager

Official source article: Cisco CISCO-SA-VOICE-RCE-MORHQY4B ↗. Check the applicable product and release in the original source.

8.2HighCVSS 3.1
Recommended action
Mitigate now

CISA confirms exploitation in the wild and lists 2026-02-11 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 21 Jan 2026

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 4.54% 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-2026-3600

CISA KEV mirrored by ENISA

A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges 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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 21 Jan 2026. Evidence sources: cisa_kev.
ENISA score
8.2 · CVSS 3.1
Advisory evidence
3 linked advisory records
Explicit mitigation evidence

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

  • csaf_ncscnl · NCSC-2026-0036Kwetsbaarheden verholpen in Cisco Unified Communications producten
Recommended actionMitigate now

CISA confirms exploitation in the wild and lists 2026-02-11 as the remediation due date.

Mitigation available
01

What, why and how

Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain a code injection vulnerability that could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.

What

Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain a code injection vulnerability that could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.

Why

Untrusted data can cross into a code-evaluation path and be interpreted as executable instructions.

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), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain a code injection vulnerability that could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.

Why

Untrusted data can cross into a code-evaluation path and be interpreted as executable instructions.

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 2026-01-21.

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
a network path → Improper Control of Generation of Code ('Code Injection') → 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
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-94 ↗

CWE-94: Improper Control of Generation of Code ('Code Injection'). The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

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:U/C:H/I:L/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.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.ILowIntegrity impact: A successful attack can cause a limited 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-94CISA KEV
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-3600Known-exploited evidence recorded

A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance could allow an unauthenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device.  This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending a sequence of crafted HTTP requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges 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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0192Cisco Unified Communications Manager, Unified Communications Manager IM & Presence Service und Unity Connection: Schwachstelle ermöglicht Codeausführung

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Cisco Unified Communications Manager (CUCM), Cisco Unified Communications Manager IM & Presence Service und Cisco Unity Connection ausnutzen, um beliebigen Programmcode auszuführen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-048Cisco security advisory (AV26-048)

On January 21, 2026, Cisco published a security advisory to address a critical vulnerability in the following products: On January 21, 2026, Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-20045 to their Known Exploited Vulnerabilities (KEV) Database.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260128Security Bulletin 28 Jan 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 28 Jan 2026, published on 28 January 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0076Vulnérabilité dans les produits Cisco

Une vulnérabilité a été découverte dans les produits Cisco. Elle permet à un attaquant de provoquer une exécution de code arbitraire à distance. Cisco indique que la vulnérabilité CVE-2026-20045 est activement exploitée.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-001875シスコシステムズのCisco Unified Communications Manager等の複数製品におけるコードインジェクションの脆弱性

Cisco Unified Communications Manager（Unified CM）、Cisco Unified Communications Manager Session Management Edition（Unified CM SME）、Cisco Unified Communications Manager IM & Presence Service（Unified CM IM&P）、Cisco Unity Connection、および Cisco Webex Calling Dedicated Instance に存在する脆弱性により、認証されていないリモートの攻撃者が影響を受けるデバイスの基盤となるオペレーティングシステム上で任意のコマンドを実行できる可能性があります。この脆弱性は、HTTPリクエストに含まれるユーザー提供の入力を不適切に検証することに起因しています。攻撃者は、細工された一連のHTTPリクエストを影響を受けるデバイスのWebベース管理インターフェースに送信することで、この脆弱性を悪用できます。攻撃が成功すると、攻撃者は基盤となるオペレーティングシステムのユーザーレベルアクセスを取得し、その後権限をrootに昇格させることが可能になります。なお、Ciscoは本セキュリティアドバイザリに対し、スコアが示す「High」ではなく「Critical」というセキュリティ影響度評価（SIR）を割り当てています。これは、この脆弱性の悪用により攻撃者が権限をrootに昇格させる可能性があるためです。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6669美 CISA 발표 주요 Exploit 정보공유(Update. 2026-01-21)

Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unity Connection, and Cisco Webex Calling Dedicated Instance contain a code injection vulnerability that could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root.

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0036Kwetsbaarheden verholpen in Cisco Unified Communications producten

A critical vulnerability in Cisco Unified Communications products allows unauthenticated remote attackers to execute arbitrary commands on the operating system due to improper input validation in HTTP requests.

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
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, perform the suggested recommendations, and apply the necessary updates when available.
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.
04

Evidence and provenance

Published 21 Jan 2026 · Last source change 26 Feb 2026, 14:44 UTC · CWE-94 · Improper Control of Generation of Code ('Code Injection')

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-2026-3600
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-av26-048.
    Before
    remediation: cyber.gc.ca/cisco-security-advisory-av26-048 · vendor advisory: sec.cloudapps.cisco.com/cisco-sa-voice-rce-mORhqY4b
    After
    vendor advisory: sec.cloudapps.cisco.com/cisco-sa-voice-rce-mORhqY4b
    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
    12.5(1)SU2; 12.5(1)SU1; 12.5(1); 12.5(1)SU3; 12.5(1)SU4; 14; 12.5(1)SU5; 14SU1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Cisco Unified Communications Manager: 12.5(1)SU2, 12.5(1)SU1, 12.5(1), 12.5(1)SU3, 12.5(1)SU4, 14, 12.5(1)SU5, 14SU1, 12.5(1)SU6, 14SU2, 12.5(1)SU7, 12.5(1)SU7a, 14SU3, 12.5(1)SU8, 12.5(1)SU8a, 15, 15SU1, 14SU4, 14SU4a, 15SU1a, 12.5(1)SU9, 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; Cisco Unified Communications Manager IM and Presence Service: 12.5(1), 12.5(1)SU1, 12.5(1)SU2, 12.5(1)SU3, 12.5(1)SU4, 14, 12.5(1)SU5, 14SU1, 12.5(1)SU6, 14SU2, 14SU2a, 12.5(1)SU7, 14SU3, 12.5(1)SU8, 15, 15SU1, 14SU4, 12.5(1)SU9, 15SU2, 15SU3; Cisco Unity Connection: 12.5(1), 12.5(1)SU1, 12.5(1)SU2, 12.5(1)SU3, 12.5(1)SU4, 14, 12.5(1)SU5, 14SU1, 12.5(1)SU6, 14SU2, 12.5(1)SU7, 14SU3, 12.5(1)SU8, 14SU3a, 12.5(1)SU8a, 15, 15SU1, 14SU4, 12.5(1)SU9, 15SU2, 15SU3 · 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-2026-3600↗Canadian Centre for Cyber Security remediation guidance↗CISA KEV record↗CVE authority or vendor reference · Cisco CISCO-SA-VOICE-RCE-MORHQY4B↗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-2026-20045 · cve.blacktree.nl