Description
A flaw was found in libslirp. When handling ICMP echo requests, the reply length is not updated to match the actual data received from the host. Under specific conditions where the normal ICMP socket is unavailable, this length mismatch causes the host's real IP address to be leaked to the guest in the echo reply, breaking the NAT isolation that user-mode networking is expected to provide.
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 | — | — |
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 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libslirp | 4.9.6-1 | — |
References
- https://access.redhat.com/security/cve/CVE-2026-115449 vdb-entry
- RHBZ#2558916 issue-tracking