Affects core network infrastructure (Cisco IOS XR). Widely deployed in telecom/enterprise networks; LPE could disrupt operations.
CVE-2026-20040
Authenticated local attacker can gain root on Cisco IOS XR via crafted CLI.
Is CVE-2026-20040 being exploited?
Not confirmed. CVE-2026-20040 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.17% probability of exploitation in the next 30 days.
How severe is CVE-2026-20040?
CVE-2026-20040 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-20040?
Yes. A fix has been recorded for CVE-2026-20040. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-20040 affect?
CVE-2026-20040 affects Cisco IOS XR devices (routers/switches). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-20040?
Patch when released; limit CLI access; use least-privilege accounts.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Privilege escalation to root via CLI argument validation; attacker with low privileges can execute arbitrary OS commands.
Patch when available
- affected6.5.3
- affected6.5.29
- affected6.5.1
- affected6.6.1
- affected6.5.2
- affected6.5.92
- affected6.5.15
- affected6.6.2
- affected7.0.1
- affected6.6.25
- affected6.5.26
- affected6.6.11
- affected6.5.25
- affected6.5.28
- affected6.5.93
- affected6.6.12
- affected6.5.90
- affected7.1.1
- affected7.0.90
- affected6.6.3
- affected6.7.1
- affected7.0.2
- affected7.1.15
- affected7.2.1
- affected7.1.2
- affected6.7.2
- affected7.0.11
- affected7.0.12
- affected7.0.14
- affected7.1.25
- affected6.6.4
- affected7.2.12
- affected7.3.1
- affected7.1.3
- affected6.7.3
- affected7.4.1
- affected7.2.2
- affected6.7.4
- affected6.5.31
- affected7.3.15
- affected7.3.16
- affected6.8.1
- affected7.4.15
- affected6.5.32
- affected7.3.2
- affected7.5.1
- affected7.4.16
- affected7.3.27
- affected7.6.1
- affected7.5.2
- affected7.8.1
- affected7.6.15
- affected7.5.12
- affected7.8.12
- affected7.3.3
- affected7.7.1
- affected6.8.2
- affected7.3.4
- affected7.4.2
- affected6.7.35
- affected6.9.1
- affected7.6.2
- affected7.5.3
- affected7.7.2
- affected6.9.2
- affected7.9.1
- affected7.10.1
- affected7.8.2
- affected7.5.4
- affected6.5.33
- affected7.8.22
- affected7.7.21
- affected7.9.2
- affected7.3.5
- affected7.5.5
- affected7.11.1
- affected7.9.21
- affected7.10.2
- affected24.1.1
- affected7.6.3
- affected7.3.6
- affected7.5.52
- affected7.11.2
- affected24.2.1
- affected24.1.2
- affected24.2.11
- affected24.3.1
- affected24.4.1
- affected24.2.2
- affected7.8.23
- affected7.11.21
- affected24.2.20
- affected24.3.2
- affected24.4.10
- affected6.5.35
- affected25.1.1
- affected24.4.2
- affected24.3.20
- affected24.4.15
- affected25.2.1
- affected6.5.351
- affected25.1.2
- affected24.3.30
- affected25.3.1
- affected6.5.352
- affected24.4.30
- affected24.2.21
- affected25.4.1
- affected25.2.2
- affected25.2.15
- affected7.2.0
- affected7.0.0
- affected25.2.30
- affected6.5.353
- affected25.1.30
- affected25.3.15
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.