libslirp TCP URG OOB Read Information Leak
CVE-2026-9539 is fixed in 2 products on 1 platform, first by libslirp0 4.9.1-1ubuntu1.1, released June 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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).
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| libslirp · Debian 13.5 (trixie) | 4.8.0-1+deb13u1 | DEBIAN-CVE-2026-9539 | Jun 24, 2026 |
| libslirp · Debian 14 | 4.9.2-1 | DEBIAN-CVE-2026-9539 | Jun 24, 2026 |
| libslirp · opensuse-leap 16.0 | 4.8.0+2-160000.3.1 | OPENSUSE-SU-2026:21216-1 | Jul 2, 2026 |
| libslirp · sles 15.7 | 4.7.0+44-150500.4.3.1 | SUSE-SU-2026:2931-1 | Jul 13, 2026 |
| libslirp0 · Ubuntu 22.04.1 LTS (jammy) | 4.6.1-1ubuntu0.2 | libslirp0 4.6.1-1ubuntu0.2 | Jul 18, 2026 |
| libslirp0 · Ubuntu 24.04.5 LTS (noble) | 4.7.0-1ubuntu3.1 | libslirp0 4.7.0-1ubuntu3.1 | Jul 18, 2026 |
| libslirp0 · Ubuntu 26.04.1 LTS (resolute) | 4.9.1-1ubuntu1.1 | libslirp0 4.9.1-1ubuntu1.1 | Jun 23, 2026 |
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