| Name | CVE-2026-9539 |
| 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). |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| libslirp (PTS) | bullseye | 4.4.0-1+deb11u2 | vulnerable |
| bookworm | 4.7.0-1 | vulnerable |
| trixie | 4.8.0-1+deb13u1 | fixed |
| forky, sid | 4.9.3-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| libslirp | source | trixie | 4.8.0-1+deb13u1 | | | |
| libslirp | source | (unstable) | 4.9.2-1 | | | |
Notes
[bookworm] - libslirp <postponed> (Minor issue, OOB read)
[bullseye] - libslirp <postponed> (Minor issue, OOB read)
https://gitlab.freedesktop.org/slirp/libslirp/-/work_items/93
https://gitlab.freedesktop.org/slirp/libslirp/-/commit/927bca7344e31fd58e2f7afaca784aad4400eb84 (v4.9.2)