Libslirp: libslirp: icmp echo reply length desynchronization leaks host ip to guest
- Published
- Last modified
- Status
- published
- Known exploitation
- Not listed in CISA KEV
- Public exploit
- None on Exploit-DB
Summary
Libslirp, the user-mode networking library used by virtualization and emulation software such as QEMU, is affected. When certain ICMP echo replies are handled, a length mismatch can expose the host's real IP address to the guest system, weakening the network isolation that NAT provides.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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 versions
- libslirp
Version range not reported
- container-tools:rhel8/libslirp
Version range not reported
- libslirp
Version range not reported
- libslirp
Version range not reported