# CVE-2026-17207: IBM i buffer overflow in NFS

Source: https://junglewise.ai/threats/cve-2026-17207-ibm-i-buffer-overflow-in-nfs  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-17207 · Severity: medium · CVSS 6.5 · Published 2026-09-04

IBM i is a critical enterprise operating system used by many Fortune 500 companies to run mission-critical business applications. A buffer overflow vulnerability in its Network File System (NFS) component allows remote attackers to crash the system and corrupt data without requiring authentication or user interaction. This can disrupt business operations and compromise the integrity of stored data.

Technologies: [IBM I 7.3](https://junglewise.ai/threats/technologies/i-7-3), [IBM I 7.4](https://junglewise.ai/threats/technologies/i-7-4), [IBM I 7.5](https://junglewise.ai/threats/technologies/i-7-5), [IBM I 7.6](https://junglewise.ai/threats/technologies/i-7-6). Vendors: [IBM](https://junglewise.ai/threats/vendors/ibm).

## Quick answers

**Is CVE-2026-17207 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-17207 being exploited in the wild.

**How severe is CVE-2026-17207?** Medium severity, with a CVSS score of 6.5, published 4 September 2026.

**Which products and versions are affected?** IBM I 7.3 7.3; IBM I 7.4 7.4; IBM I 7.5 7.5; IBM I 7.6 7.6.

**Is there a fix for CVE-2026-17207?** A patch was published on 2026-09-04: PTF SJ11320 (7.6), SJ11319 (7.5), SJ11318 (7.4), SJ11317 (7.3) Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-17207 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-17207?** Check whether you run IBM I 7.3, IBM I 7.4, IBM I 7.5 or one of the others listed 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

A buffer overflow vulnerability (CWE-787: Out-of-bounds Write) exists in the Network File System (NFS) implementation within IBM i versions 7.3 through 7.6. The vulnerability is remotely exploitable over the network without authentication, precondition, or user interaction (CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U). An attacker can send a specially crafted NFS request to trigger the out-of-bounds write, leading to denial of service and data integrity compromise. IBM has released platform-specific patches (PTFs SJ11317 through SJ11320) for all affected versions.

## Affected products

- IBM i 7.6 7.6
- IBM i 7.5 7.5
- IBM i 7.4 7.4
- IBM i 7.3 7.3

## Timeline

- 2026-09-04: disclosed
- 2026-09-04: patched: PTF SJ11320 (7.6), SJ11319 (7.5), SJ11318 (7.4), SJ11317 (7.3)

## References

- [https://www.ibm.com/support/pages/node/7285847](https://www.ibm.com/support/pages/node/7285847)

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