CVE-2026-115449

Libslirp: libslirp: icmp echo reply length desynchronization leaks host ip to guest

Published Oct 22, 2026 CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Workaround

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.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Libslirp: libslirp: icmp echo reply length desynchronization leaks host ip to guest
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-200
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N'}

threat_severity

Low

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Nov 6, 2026, 5:51 PM
Reserved
Oct 22, 2026, 2:40 PM
Status
Awaiting Analysis
Published
Oct 22, 2026, 10:18 PM
Modified
Nov 6, 2026, 6:17 PM
Severity
Low
Public date
Oct 22, 2026, 12:00 AM