CVE-2026-9539 | An out-of-bounds heap read and integer underflow in the TCP … | CVSS 6.5 MEDIUM

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).

Metadata

CVE ID: CVE-2026-9539
State: PUBLISHED
Assigner: STAR_Labs
Reserved: 2026-05-26 02:36 UTC
Published: 2026-06-24 04:37 UTC
Last updated: 2026-06-24 04:37 UTC
Primary CWE: CWE-125
CWE-125 Out-of-bounds read
Vendor / Product: freedesktop.org / libslirp
Sources: cve.org · NVD

Severity & Metrics

6.5 MEDIUM CVSS 3.1

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

Affected products (1)

Vendor	Product	Platform	Versions
freedesktop.org	libslirp	—	0 < 4.9.2

Weakness (CWE)

CWE	Source	Description
CWE-125	cna	CWE-125 Out-of-bounds read

CVSS scores (1)

Score	Severity	Version	Source	Vector
6.5	MEDIUM	3.1	cna	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

References (3)