# CVE-2026-57965: Red Hat spice-vdagent integer overflow in udscs_write

Source: https://junglewise.ai/threats/cve-2026-57965-red-hat-spice-vdagent-integer-overflow-in-udscs-write  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-29. Updated: 2026-06-29  
License: CC BY 4.0 with a link back

CVE-2026-57965 · Severity: medium · CVSS 5.1 · Published 2026-06-29

A vulnerability exists in the SPICE agent, a tool used to improve the user experience in virtual machines by enabling features like clipboard sharing and file transfers. A compromised or malicious host server can send a specially crafted message to the virtual machine, causing the agent to crash. This results in a denial of service for the virtual machine's integration features, though it typically requires the host server to already be compromised.

Technologies: [Red Hat Enterprise Linux 10](https://junglewise.ai/threats/technologies/enterprise-linux-10), [Red Hat Enterprise Linux 6](https://junglewise.ai/threats/technologies/enterprise-linux-6), [Red Hat Enterprise Linux 7](https://junglewise.ai/threats/technologies/enterprise-linux-7), [Red Hat Enterprise Linux 8](https://junglewise.ai/threats/technologies/enterprise-linux-8), [Red Hat Enterprise Linux 9](https://junglewise.ai/threats/technologies/enterprise-linux-9). Vendors: [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-57965 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57965 being exploited in the wild.

**How severe is CVE-2026-57965?** Medium severity, with a CVSS score of 5.1, published 29 June 2026.

**Which products and versions are affected?** Red Hat Enterprise Linux 10 affected status; Red Hat Enterprise Linux 6 affected status; Red Hat Enterprise Linux 7 affected status; Red Hat Enterprise Linux 8 affected status; and 1 more.

**Is there a fix for CVE-2026-57965?** 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-2026-57965 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-57965?** Check whether you run Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7 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

An integer overflow vulnerability exists in the udscs_write() function within src/udscs.c of spice-vdagent. The function calculates a buffer size using 32-bit unsigned integers (guint) without proper bounds checking; specifically, when a large 'size' value is provided in a VDAgentMessage (such as clipboard or file transfers), the calculation wraps around to a small value. This leads to a heap buffer overflow during a subsequent memcpy operation. While the attack vector is local to the guest, it is triggered by the SPICE host. Exploitation results in a SIGBUS crash of the spice-vdagent daemon, causing a Denial of Service (DoS) for guest-host integration features. The vulnerability is confirmed via AddressSanitizer.

## Affected products

- Red Hat Red Hat Enterprise Linux 6 affected status
- Red Hat Red Hat Enterprise Linux 7 affected status
- Red Hat Red Hat Enterprise Linux 8 affected status
- Red Hat Red Hat Enterprise Linux 9 affected status
- Red Hat Red Hat Enterprise Linux 10 affected status
- SPICE Project spice-vdagent

## Timeline

- 2026-06-26: disclosed: Initial report in Red Hat Bugzilla
- 2026-06-29: advisory: CVE published to NVD dataset

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-57965](https://access.redhat.com/security/cve/CVE-2026-57965)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2493581](https://bugzilla.redhat.com/show_bug.cgi?id=2493581)

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