CVE-2026-9539

Publication date 24 June 2026

Last updated 10 July 2026

Ubuntu priority

Cvss 3 Severity Score

Description

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).

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libslirp	26.04 LTS resolute	Needs evaluation
	25.10 questing	Ignored end of life, was needs-triage
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libslirp	Upstream: 927bca7

Severity score breakdown

CVSS version: CVSS v3.0

Base score 6.5 · Medium

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Changed
Confidentiality impact	High
Integrity impact	None
Availability impact	None

Scores

Parameter	Value
Base score	6.5 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N