Medium 6.5Published Jun 24, 2026

CVE-2026-9539libslirp TCP URG OOB Read Information Leak

Updated under an hour ago (Oct 26, 2026, 1:23 PM ET)

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It affects freedesktop.org libslirp. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for freedesktop.org libslirp

Exploited in the last 30 days

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: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Weakness (CWE): CWE-125
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: STAR_Labs
NVD analysis: Awaiting Analysis
Record last updated: Jun 24, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

freedesktop.org libslirp freedesktop.org:libslirp (from the name)	before 4.9.2; fixed at 4.9.2	CNA record

References

References

https://gitlab.freedesktop.org/slirp/libslirp/-/work_items/93	issue-tracking
https://gitlab.freedesktop.org/slirp/libslirp/-/commit/927bca7344e31fd58e2f7afaca784aad4400eb84	patch
https://gitlab.freedesktop.org/slirp/libslirp/-/releases/v4.9.2	release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.