CVE-2026-95508
HighCVSS 7.4Exploitation Probability (EPSS)
Low risk36th percentile - higher than 36% of all known CVEs
Summary
A heap-based buffer overflow was found in the DHCPv6 and TFTP response builders of libslirp. When the host is configured with a small interface MTU, a guest-supplied DHCPv6 CLIENTID option or TFTP blksize option can overflow the reply buffer with attacker-controlled content and length, resulting in denial of service and potentially arbitrary code execution in the host process. The default interface MTU is not affected.
Risk Assessment
An attacker from the guest could cause denial of service or execute arbitrary code in the host process, potentially leading to host compromise.
Recommendation
Update libslirp to a patched version or avoid configurations with a small interface MTU.
Other vulnerabilities in libslirp
See all- CVE-2026-120831Medium
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.
- CVE-2026-120830High
A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.
- CVE-2026-95507Medium
An out-of-bounds read was found in the NC-SI OEM response handler of libslirp. A truncated NC-SI OEM Ethernet frame causes ncsi_rsp_handler_oem() to read up to 4 bytes beyond the supplied packet length and reflect the value into the response sent to the guest, resulting in guest-observable disclosure.
- CVE-2026-115449Low
A flaw was found in libslirp where, 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.
Original NVD description (English source)
A heap-based buffer overflow was found in the DHCPv6 and TFTP response builders of libslirp. When the host is configured with a small interface MTU, a guest-supplied DHCPv6 CLIENTID option or TFTP blksize option can overflow the reply buffer with attacker-controlled content and length, resulting in denial of service and potentially arbitrary code execution in the host process. The default interface MTU is not affected.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS