Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.42% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-20206High confidence
Cisco ThousandEyes BrowserBot Command Injection Vulnerability
Cisco · Cisco ThousandEyes Enterprise Agent
Official source article: Cisco CISCO-SA-TEBBOT-CMDINJ-WN3YQ5GN ↗. Check the applicable product and release in the original source.
6.3MediumCVSS 3.1
Scheduled
Fix not verifiedMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
Compensating controls
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Cisco Cisco ThousandEyes Enterprise Agent and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Fix not verified01
What, why and how
A vulnerability in the BrowserBot component of Cisco ThousandEyes Enterprise Agent could have allowed an authenticated, remote attacker to execute arbitrary commands on Agents on behalf of the BrowserBot synthetics orchestration process. Cisco has addressed this vulnerability in the Cisco ThousandEyes Enterprise Agent, and no customer action is needed. This vulnerability was due to insufficient input validation of command arguments that are supplied by the user. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by authenticating to the ThousandEyes SaaS and submitting crafted input into the affected parameter. A successful exploit could have allowed the attacker to execute arbitrary commands within the BrowserBot container as the node user. To exploit this vulnerability, the attacker must have valid user credentials for the ThousandEyes SaaS and the ability to manage transaction tests.
What
A vulnerability in the BrowserBot component of Cisco ThousandEyes Enterprise Agent could have allowed an authenticated, remote attacker to execute arbitrary commands on Agents on behalf of the BrowserBot synthetics orchestration process. Cisco has addressed this vulnerability in the Cisco ThousandEyes Enterprise Agent, and no customer action is needed. This vulnerability was due to insufficient input validation of command arguments that are supplied by the user. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by authenticating to the ThousandEyes SaaS and submitting crafted input into the affected parameter. A successful exploit could have allowed the attacker to execute arbitrary commands within the BrowserBot container as the node user. To exploit this vulnerability, the attacker must have valid user credentials for the ThousandEyes SaaS and the ability to manage transaction tests.
Why
Untrusted input is incorporated into an operating-system command without safe parameter handling.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
What
A vulnerability in the BrowserBot component of Cisco ThousandEyes Enterprise Agent could have allowed an authenticated, remote attacker to execute arbitrary commands on Agents on behalf of the BrowserBot synthetics orchestration process. Cisco has addressed this vulnerability in the Cisco ThousandEyes Enterprise Agent, and no customer action is needed. This vulnerability was due to insufficient input validation of command arguments that are supplied by the user. Prior to this vulnerability being addressed, an attacker could have exploited this vulnerability by authenticating to the ThousandEyes SaaS and submitting crafted input into the affected parameter. A successful exploit could have allowed the attacker to execute arbitrary commands within the BrowserBot container as the node user. To exploit this vulnerability, the attacker must have valid user credentials for the ThousandEyes SaaS and the ability to manage transaction tests.
Why
Untrusted input is incorporated into an operating-system command without safe parameter handling.
How
An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 Neutralization of Special Elements used in an OS Command ('OS Command Injection') → execute code or commands in the affected security context
- Attack surface
- Network
- 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-78 ↗
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
- 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:L/UI:N/S:U/C:L/I:L/A:LCommon 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.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.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ALowAvailability impact: A successful attack can cause a limited loss.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
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
- Cisco ThousandEyes Enterprise Agent: Agent 5.0, Agent 4.4.4, Agent 4.4.3, Agent 4.4.2, Agent 4.2, Agent 4.1, Agent 4.0, Agent 5.1, Agent 5.1.2, Agent 5.1.3
- 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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 20 May 2026 · Last source change 21 May 2026, 13:06 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-31136
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
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
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.