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CVE-2026-20268

HIGH 8.6 ALL-YEARS

Published 2026-08-05 · Last modified 2026-10-02 · cisco · NVD: Modified

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20268 are related to issues with improper restriction of operations within the bounds of a memory buffer that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-119.

ELEVATED IMPACT

Severe if exploited (CVSS 8.6), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 40th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

8.6CVSS 3.1 · HIGH · CNA

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Cisco

Products Cisco Ios Xe Software Ios Xe

Weakness (CWE)

  • CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

References and research data (JSON)

Known Affected Software Configurations

VendorProductVersion range
CiscoIos Xe16.6.2
CiscoIos Xe16.6.3
CiscoIos Xe16.6.4
CiscoIos Xe16.6.4a
CiscoIos Xe16.6.4s
CiscoIos Xe16.6.5
CiscoIos Xe16.6.5a
CiscoIos Xe16.6.5b
CiscoIos Xe16.6.6
CiscoIos Xe16.6.7
CiscoIos Xe16.6.7a
CiscoIos Xe16.6.8
CiscoIos Xe16.6.9
CiscoIos Xe16.6.10
CiscoIos Xe16.7.1
CiscoIos Xe16.7.1a
CiscoIos Xe16.7.1b
CiscoIos Xe16.7.2
CiscoIos Xe16.7.3
CiscoIos Xe16.7.4
CiscoIos Xe16.8.1
CiscoIos Xe16.8.1a
CiscoIos Xe16.8.1b
CiscoIos Xe16.8.1c
CiscoIos Xe16.8.1d
CiscoIos Xe16.8.1e
CiscoIos Xe16.8.1s
CiscoIos Xe16.8.2
CiscoIos Xe16.8.3
CiscoIos Xe16.9.1
CiscoIos Xe16.9.1a
CiscoIos Xe16.9.1b
CiscoIos Xe16.9.1c
CiscoIos Xe16.9.1d
CiscoIos Xe16.9.1s
CiscoIos Xe16.9.2
CiscoIos Xe16.9.2a
CiscoIos Xe16.9.2s
CiscoIos Xe16.9.3
CiscoIos Xe16.9.3a
CiscoIos Xe16.9.3h
CiscoIos Xe16.9.3s
CiscoIos Xe16.9.4
CiscoIos Xe16.9.4c
CiscoIos Xe16.9.5
CiscoIos Xe16.9.5f
CiscoIos Xe16.9.6
CiscoIos Xe16.9.7
CiscoIos Xe16.9.8
CiscoIos Xe16.9.8a
CiscoIos Xe16.9.8b
CiscoIos Xe16.10.1
CiscoIos Xe16.10.1a
CiscoIos Xe16.10.1b
CiscoIos Xe16.10.1c
CiscoIos Xe16.10.1d
CiscoIos Xe16.10.1e
CiscoIos Xe16.10.1f
CiscoIos Xe16.10.1g
CiscoIos Xe16.10.1s
CiscoIos Xe16.10.2
CiscoIos Xe16.10.3
CiscoIos Xe16.11.1
CiscoIos Xe16.11.1a
CiscoIos Xe16.11.1b
CiscoIos Xe16.11.1c
CiscoIos Xe16.11.1s
CiscoIos Xe16.11.2
CiscoIos Xe16.12.1
CiscoIos Xe16.12.1a
CiscoIos Xe16.12.1c
CiscoIos Xe16.12.1s
CiscoIos Xe16.12.1t
CiscoIos Xe16.12.1w
CiscoIos Xe16.12.1x
CiscoIos Xe16.12.1y
CiscoIos Xe16.12.1z
CiscoIos Xe16.12.1z1
CiscoIos Xe16.12.1z2
CiscoIos Xe16.12.2
CiscoIos Xe16.12.2a
CiscoIos Xe16.12.2s
CiscoIos Xe16.12.2t
CiscoIos Xe16.12.3
CiscoIos Xe16.12.3a
CiscoIos Xe16.12.3s
CiscoIos Xe16.12.4
CiscoIos Xe16.12.4a
CiscoIos Xe16.12.5
CiscoIos Xe16.12.5a
CiscoIos Xe16.12.5b
CiscoIos Xe16.12.6
CiscoIos Xe16.12.6a
CiscoIos Xe16.12.7
CiscoIos Xe16.12.8
CiscoIos Xe16.12.9
CiscoIos Xe16.12.10
CiscoIos Xe16.12.10a
CiscoIos Xe16.12.11
CiscoIos Xe16.12.12
CiscoIos Xe16.12.13
CiscoIos Xe16.12.14
CiscoIos Xe16.12.15
CiscoIos Xe16.12.16
CiscoIos Xe17.1.1
CiscoIos Xe17.1.1a
CiscoIos Xe17.1.1s
CiscoIos Xe17.1.1t
CiscoIos Xe17.1.2
CiscoIos Xe17.1.3
CiscoIos Xe17.2.1
CiscoIos Xe17.2.1a
CiscoIos Xe17.2.1r
CiscoIos Xe17.2.1v
CiscoIos Xe17.2.2
CiscoIos Xe17.2.3
CiscoIos Xe17.3.1
CiscoIos Xe17.3.1a
CiscoIos Xe17.3.1w
CiscoIos Xe17.3.1x

Showing 120 of 250+ configuration entries. Full list on NVD.

All CVSS metrics

  • HIGH 8.6 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
  • HIGH 8.6 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS