CVE catalog
CVE-2026-9539
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 pri
- Severity
- Medium · CVSS 6.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.22% · Oct 25, 2026
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).
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | libslirp | sid | 4.9.5-1 | fixed |
| Debian | libslirp | forky | 4.9.5-1 | fixed |
| Debian | libslirp | trixie | 4.8.0-1+deb13u1 | fixed |
| Debian | libslirp | bookworm | 4.7.0-1 | vulnerable |
| Cpe | libslirp | Not reported | Not reported | vulnerable |
| Cpe | libslirp | Not reported | 4.7.0-1ubuntu3.1 | fixed |
| Cpe | libslirp-dev | Not reported | 4.7.0-1ubuntu3.1 | fixed |
| Cpe | libslirp0 | Not reported | 4.7.0-1ubuntu3.1 | fixed |
| Ubuntu | libslirp | 22.04 | 4.4.0-1build1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1build1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1ubuntu0.2 | fixed |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu2 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu3 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu3.1 | fixed |
| Ubuntu | libslirp | 26.04 | 4.8.0-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 26.04 | 4.9.1-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 26.04 | 4.9.1-1ubuntu1.1 | fixed |
| Ubuntu | libslirp | 20.04 | 4.0.0-1 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.0.0-2 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-1 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-2 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-2ubuntu1 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-2ubuntu2 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-2ubuntu2.1 | vulnerable |
| Ubuntu | libslirp | 20.04 | 4.1.0-2ubuntu2.2 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.4.0-1build1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1build1 | vulnerable |
| Ubuntu | libslirp | 22.04 | 4.6.1-1ubuntu0.2 | fixed |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu2 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu3 | vulnerable |
| Ubuntu | libslirp | 24.04 | 4.7.0-1ubuntu3.1 | fixed |
| Ubuntu | libslirp | 25.10 | 4.8.0-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 26.04 | 4.8.0-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 26.04 | 4.9.1-1ubuntu1 | vulnerable |
| Ubuntu | libslirp | 26.04 | 4.9.1-1ubuntu1.1 | fixed |
| Suse | libslirp | linux enterprise micro 5.5 | 4.7.0+44-150500.4.3.1 | fixed |
| Suse | libslirp | linux enterprise module for basesystem 15 sp7 | 4.7.0+44-150500.4.3.1 | fixed |
| Suse | libslirp | linux enterprise micro 5.3 | 4.7.0+44-150300.18.1 | fixed |
| Suse | libslirp | linux enterprise micro 5.4 | 4.7.0+44-150300.18.1 | fixed |
| Suse | libslirp | linux micro 6.0 | 4.7.0+44-5.1 | fixed |
| Suse | libslirp | linux micro 6.1 | 4.8.0+2-slfo.1.1_2.1 | fixed |
| Opensuse | libslirp | leap 16.0 | 4.8.0+2-160000.3.1 | fixed |
| Opensuse | libslirp | tumbleweed | 4.9.3+4-1.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libslirp | source | sid | 4.9.2-1 | not yet assigned | Not reported | Not reported |
| Debian | libslirp | source | forky | 4.9.2-1 | not yet assigned | Not reported | Not reported |
| Debian | libslirp | source | trixie | 4.8.0-1+deb13u1 | not yet assigned | Not reported | Not reported |
| Debian | libslirp | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | libslirp | cpe | Not reported | 4.7.0-1ubuntu3.1 | Not reported | Not reported | Not reported |
| Cpe | libslirp-dev | cpe | Not reported | 4.7.0-1ubuntu3.1 | Not reported | Not reported | Not reported |
| Cpe | libslirp0 | cpe | Not reported | 4.7.0-1ubuntu3.1 | Not reported | Not reported | Not reported |
| Ubuntu | libslirp | deb | 22.04 | 4.6.1-1ubuntu0.2 | Not reported | USN-8550-1 | Not reported |
| Ubuntu | libslirp | deb | 24.04 | 4.7.0-1ubuntu3.1 | Not reported | USN-8550-1 | Not reported |
| Ubuntu | libslirp | deb | 26.04 | 4.9.1-1ubuntu1.1 | Not reported | USN-8550-1 | Not reported |
| Ubuntu | libslirp | deb | 22.04 | 4.6.1-1ubuntu0.2 | Not reported | UBUNTU-CVE-2026-9539 | Not reported |
| Ubuntu | libslirp | deb | 24.04 | 4.7.0-1ubuntu3.1 | Not reported | UBUNTU-CVE-2026-9539 | Not reported |
| Ubuntu | libslirp | deb | 26.04 | 4.9.1-1ubuntu1.1 | Not reported | UBUNTU-CVE-2026-9539 | Not reported |
| Suse | libslirp | rpm | linux enterprise micro 5.5 | 4.7.0+44-150500.4.3.1 | Not reported | SUSE-SU-2026:2931-1 | Not reported |
| Suse | libslirp | rpm | linux enterprise module for basesystem 15 sp7 | 4.7.0+44-150500.4.3.1 | Not reported | SUSE-SU-2026:2931-1 | Not reported |
| Suse | libslirp | rpm | linux enterprise micro 5.3 | 4.7.0+44-150300.18.1 | Not reported | SUSE-SU-2026:2886-1 | Not reported |
| Suse | libslirp | rpm | linux enterprise micro 5.4 | 4.7.0+44-150300.18.1 | Not reported | SUSE-SU-2026:2886-1 | Not reported |
| Suse | libslirp | rpm | linux micro 6.0 | 4.7.0+44-5.1 | Not reported | SUSE-SU-2026:22514-1 | Not reported |
| Suse | libslirp | rpm | linux micro 6.1 | 4.8.0+2-slfo.1.1_2.1 | Not reported | SUSE-SU-2026:22452-1 | Not reported |
| Opensuse | libslirp | rpm | leap 16.0 | 4.8.0+2-160000.3.1 | Not reported | OPENSUSE-SU-2026:21216-1 | Not reported |
| Opensuse | libslirp | rpm | tumbleweed | 4.9.3+4-1.1 | Not reported | OPENSUSE-SU-2026:11134-1 | Not reported |
Notes
[bookworm] libslirp: Minor issue, OOB read
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libslirp0]Affected
Source package: [libslirp]
Details (2)
4.7.0-1· amd64 · bookwormAffected
nvd · libslirp · debian · bookworm; nvd · libslirp · debian · 12
4.7.0-1· arm64 · bookwormAffected
nvd · libslirp · debian · bookworm; nvd · libslirp · debian · 12
- [libslirp-dev]Affected
Source package: [libslirp]
Details (2)
4.7.0-1· amd64 · bookwormAffected
nvd · libslirp · debian · bookworm; nvd · libslirp · debian · 12
4.7.0-1· arm64 · bookwormAffected
nvd · libslirp · debian · bookworm; nvd · libslirp · debian · 12
[openSUSE Tumbleweed]
- [libslirp0]Unknown
Source package: [libslirp]
Details (1)
4.9.3+4-1.3· x86_64 · tumbleweedUnknown · Fixed:
4.9.3+4-1.1Version impact unknown
nvd · libslirp · opensuse · tumbleweed
- [libslirp-devel]Unknown
Source package: [libslirp]
Details (1)
4.9.3+4-1.3· x86_64 · tumbleweedUnknown · Fixed:
4.9.3+4-1.1Version impact unknown
nvd · libslirp · opensuse · tumbleweed
[Debian 13 (Trixie)]
- [libslirp0]Fixed
Source package: [libslirp]
Details (2)
4.8.0-1+deb13u1· amd64 · trixieFixed · Fixed:
4.8.0-1+deb13u1nvd · libslirp · debian · 13
4.8.0-1+deb13u1· arm64 · trixieFixed · Fixed:
4.8.0-1+deb13u1nvd · libslirp · debian · 13
- [libslirp-dev]Fixed
Source package: [libslirp]
Details (2)
4.8.0-1+deb13u1· amd64 · trixieFixed · Fixed:
4.8.0-1+deb13u1nvd · libslirp · debian · 13
4.8.0-1+deb13u1· arm64 · trixieFixed · Fixed:
4.8.0-1+deb13u1nvd · libslirp · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/]
- [https://gitlab.freedesktop.org/slirp/libslirp/-/commit/927bca7344e31fd58e2f7afaca784aad4400eb84]
- [https://gitlab.freedesktop.org/slirp/libslirp/-/releases/v4.9.2]
- [https://gitlab.freedesktop.org/slirp/libslirp/-/work_items/93]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-9539]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-9539]
- [https://osv.dev/vulnerability/SUSE-SU-2026:22452-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:22514-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:2886-1]
- [https://osv.dev/vulnerability/SUSE-SU-2026:2931-1]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-9539]
- [https://osv.dev/vulnerability/USN-8550-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:11134-1]
- [https://osv.dev/vulnerability/openSUSE-SU-2026:21216-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-9539]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9539.json]
- [https://ubuntu.com/security/notices/USN-8550-1]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]