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Full vulnerability report · 2026
CVE-2026-20040High confidence

Cisco IOS XR Software CLI Privilege Escalation Vulnerability

Cisco · Cisco IOS XR Software

8.8HighCVSS 3.1
Recommended action
Within 7 days

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

Fix not verified
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2026-11214

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.

Fix not verified
01

What, why and how

A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.

What

A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through local access 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 CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through local access 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
?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
local access → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → execute code or commands in the affected security context
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
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-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:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

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

AVLocalAttack vector: The attacker needs local access to the vulnerable system.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.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major 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.
Remote code executionPrivilege escalationCWE-78
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-0706Cisco IOS XR: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Cisco IOS XR ausnutzen, um seine Privilegien zu erhöhen, um beliebigen Code mit root-rechten auszuführen, und um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0279Multiples vulnérabilités dans Cisco IOS XR

De multiples vulnérabilités ont été découvertes dans Cisco IOS XR. Certaines d'entre elles permettent à un attaquant de provoquer une élévation de privilèges et un déni de service à distance. L'éditeur fournit des recommandations dans l'attente de la publication de nouvelles versions applicatives.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-021839シスコシステムズのCisco IOS XRにおけるOS コマンドインジェクションの脆弱性

Cisco IOS XRソフトウェアのCLIに存在する脆弱性により、認証されたローカル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root権限として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、特定のCLIコマンドに渡されるユーザー引数の検証不足が原因です。低権限のアカウントを持つ攻撃者は、プロンプトで細工されたコマンドを使用してこの脆弱性を悪用できます。悪用に成功すると、権限をrootに昇格させて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ます。

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0094Kwetsbaarheden verholpen in Cisco IOS XR

Multiple vulnerabilities in Cisco IOS XR Software CLI allow authenticated local attackers to execute arbitrary root-level commands or gain full administrative control due to insufficient validation of user arguments.

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.
Fix not verified
Affected
Cisco IOS XR Software: 6.5.3, 6.5.29, 6.5.1, 6.6.1, 6.5.2, 6.5.92, 6.5.15, 6.6.2, 7.0.1, 6.6.25, 6.5.26, 6.6.11, 6.5.25, 6.5.28, 6.5.93, 6.6.12, 6.5.90, 7.1.1, 7.0.90, 6.6.3, 6.7.1, 7.0.2, 7.1.15, 7.2.1, 7.1.2, 6.7.2, 7.0.11, 7.0.12, 7.0.14, 7.1.25, 6.6.4, 7.2.12, 7.3.1, 7.1.3, 6.7.3, 7.4.1, 7.2.2, 6.7.4, 6.5.31, 7.3.15, 7.3.16, 6.8.1, 7.4.15, 6.5.32, 7.3.2, 7.5.1, 7.4.16, 7.3.27, 7.6.1, 7.5.2, 7.8.1, 7.6.15, 7.5.12, 7.8.12, 7.3.3, 7.7.1, 6.8.2, 7.3.4, 7.4.2, 6.7.35, 6.9.1, 7.6.2, 7.5.3, 7.7.2, 6.9.2, 7.9.1, 7.10.1, 7.8.2, 7.5.4, 6.5.33, 7.8.22, 7.7.21, 7.9.2, 7.3.5, 7.5.5, 7.11.1, 7.9.21, 7.10.2, 24.1.1, 7.6.3, 7.3.6, 7.5.52, 7.11.2, 24.2.1, 24.1.2, 24.2.11, 24.3.1, 24.4.1, 24.2.2, 7.8.23, 7.11.21, 24.2.20, 24.3.2, 24.4.10, 6.5.35, 25.1.1, 24.4.2, 24.3.20, 24.4.15, 25.2.1, 6.5.351, 25.1.2, 24.3.30, 25.3.1, 6.5.352, 24.4.30, 24.2.21, 25.4.1, 25.2.2, 25.2.15, 7.2.0, 7.0.0, 25.2.30, 6.5.353, 25.1.30, 25.3.15
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. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 11 Mar 2026 · Last source change 12 Mar 2026, 03:55 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
?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-2026-11214
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
CVE published
ENISA EUVD · EUVD-2026-11214↗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-2026-20040 · cve.blacktree.nl