CVE-2026-9539 Affecting libslirp package, versions <4.9.1-1ubuntu1.1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.22% (13th percentile)

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  • Snyk IDSNYK-UBUNTU2604-LIBSLIRP-17487020
  • published16 Jul 2026
  • disclosed24 Jun 2026

Introduced: 24 Jun 2026

CVE-2026-9539  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 libslirp to version 4.9.1-1ubuntu1.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libslirp package and not the libslirp package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp).

CVSS Base Scores

version 3.1