Is CVE-2026-20275 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-20275 being exploited in the wild.

How severe is CVE-2026-20275?

High severity, with a CVSS score of 8.8, published 2 September 2026.

Which products and versions are affected?

Cisco IOS XR Software all releases including IOS XR7 (LNT).

Is there a fix for CVE-2026-20275?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-20275 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-20275?

Check whether you run Cisco IOS XR Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-20275: Cisco IOS XR Software incorrect calculation vulnerability

CVE-2026-20275 · Severity: high · CVSS 8.8 · Published 2026-09-02

Cisco IOS XR Software, used in network routing and infrastructure equipment, contains an incorrect calculation vulnerability that could allow an unauthenticated remote attacker to compromise system integrity and availability. The vulnerability stems from integer overflow or underflow issues during internal security hardening review and affects all IOS XR releases. Cisco has released software updates to address this issue, with no workarounds available.

Technologies: Cisco IOS XR Software. Vendors: Cisco.

Quick answers

Is CVE-2026-20275 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-20275 being exploited in the wild.
How severe is CVE-2026-20275?: High severity, with a CVSS score of 8.8, published 2 September 2026.
Which products and versions are affected?: Cisco IOS XR Software all releases including IOS XR7 (LNT).
Is there a fix for CVE-2026-20275?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-20275 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-20275?: Check whether you run Cisco IOS XR Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

CVE-2026-20275 represents a class of incorrect calculation vulnerabilities (CWE-682) in Cisco IOS XR Software, specifically covering integer overflow, integer underflow, and buffer size calculation errors. The vulnerability is remotely exploitable without authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). An attacker can exploit this to achieve high confidentiality, integrity, and availability impact. The issue was discovered during internal security review and is not known to be actively exploited. Cisco has released patched software versions and recommends customers upgrade to the fixed releases listed in the advisory or apply available SMUs.

Affected products

Cisco IOS XR Software all releases including IOS XR7 (LNT)

Timeline

2026-09-02: disclosed
2026-09-17: other: Advisory last updated

References

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