Libslirp: libslirp: icmp echo reply length desynchronization leaks host ip to guest
Summary
| CVE | CVE-2026-115449 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-22 22:18:06 UTC |
| Updated | 2026-10-22 22:18:06 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 3.5 LOW from [email protected]
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
Problem Types: CWE-200 | CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 3.5 | LOW | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N |
| 3.1 | CNA | CVSS | 3.5 | LOW | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
ChangedConfidentiality
LowIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-115449 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Piyusha Akash for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-10-21T06:10:30.000Z | Reported to Red Hat. |
| CNA | 2026-10-22T00:00:00.000Z | Made public. |
Workarounds
CNA: Ensure that the QEMU process user's GID is included in the system's ping_group_range (sysctl net.ipv4.ping_group_range), which allows the SOCK_DGRAM ICMP socket path and avoids the vulnerable raw socket fallback. Alternatively, use --net none or virtio-net with a TAP backend instead of user-mode (slirp) networking.
There are currently no legacy QID mappings associated with this CVE.