# CVE-2026-86846: DPDK vhost-crypto out-of-bounds write via unchecked descriptor index

Source: https://junglewise.ai/threats/cve-2026-86846-a-flaw-was-found-in-dpdk-lib-vhost-vhost-crypto-a-guest-can  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-14. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-86846 · Severity: medium · CVSS 6.5 · Published 2026-10-14

DPDK is a data plane software library used in virtualized networking. A flaw in its vhost-crypto component allows a malicious guest virtual machine to write to memory outside bounds in the host system, potentially causing the vhost backend to crash or become unstable. This affects only systems that have built and enabled the vhost-crypto feature and attach it to untrusted guests.

Technologies: [DPDK](https://junglewise.ai/threats/technologies/dpdk). Vendors: [DPDK](https://junglewise.ai/threats/vendors/dpdk).

## Quick answers

**Is CVE-2026-86846 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86846 being exploited in the wild.

**How severe is CVE-2026-86846?** Medium severity, with a CVSS score of 6.5, published 14 October 2026.

**Which products and versions are affected?** DPDK <UNKNOWN>.

**Is there a fix for CVE-2026-86846?** No fixed version is recorded yet. Do not attach a virtio-crypto vhost-user backend to untrusted guests. 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-2026-86846 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-86846?** Check whether you run DPDK 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.

## How to fix


Do not attach a virtio-crypto vhost-user backend to untrusted guests.

## Technical details

The vulnerability is an out-of-bounds write (CWE-787) in DPDK's lib/vhost vhost-crypto backend. A guest with access to a virtio-crypto vhost-user device can supply an avail-ring descriptor index that lacks bounds checking, leading to an out-of-bounds write in host memory. Attack requires local/adjacent network access from the guest, low privileges, and no user interaction; impact is primarily availability (host crash or instability).

## Affected products

- DPDK DPDK <UNKNOWN>

## Timeline

- 2026-10-14: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-86846](https://access.redhat.com/security/cve/CVE-2026-86846)

## Related threats

- [DPDK vhost-crypto integer overflow in lib/vhost](https://junglewise.ai/threats/cve-2026-86849-a-flaw-was-found-in-dpdk-lib-vhost-vhost-crypto-integer-overflow)
- [DPDK vhost-crypto indirect-descriptor double-fetch out-of-bounds](https://junglewise.ai/threats/cve-2026-86848-a-flaw-was-found-in-dpdk-lib-vhost-vhost-crypto-the-indirect)
- [DPDK vhost-crypto uninitialized pointer in write-back chain](https://junglewise.ai/threats/cve-2026-86847-a-flaw-was-found-in-dpdk-lib-vhost-vhost-crypto-write-back-chain)
- [DPDK lib/vhost use-after-free in VDUSE handler](https://junglewise.ai/threats/cve-2026-86567-a-flaw-was-found-in-dpdk-lib-vhost-the-vduse-handler-fails-to)
- [DPDK lib/vhost integer underflow in RX descriptor processing](https://junglewise.ai/threats/cve-2026-86566-a-flaw-was-found-in-dpdk-lib-vhost-a-guest-with-runt-rx)