Description
A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libslirp | No fix yet | — |
| Debian 13 | libslirp | No fix yet | — |
| Debian 12 | libslirp | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libslirp | No fix yet | — |
| Ubuntu 26.04 LTS | libslirp | No fix yet | — |
| Ubuntu 24.04 LTS | libslirp | No fix yet | — |
| Ubuntu 22.04 LTS | libslirp | No fix yet | — |
| Ubuntu 20.04 LTS | libslirp | No fix yet | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | qemu +26 | 10:3.1.0-8.amzn2.0.30 | ALAS2-2026-4102 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libslirp | 4.9.7-1 | — |
Advisories 1
- ALAS2-2026-4102 Important: qemu security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 12, 2026