{"id":"CVE-2026-4747","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-4747","generatedAt":"2026-10-28T04:44:42.984Z","title":"This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow.","description":"Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet.  This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow.  Notably, this does not require the client to authenticate itself first.\n\nAs kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel.\n\nIn userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets.  We are not aware of any such applications in the FreeBSD base system.","published":"2026-03-26T07:16:21.000Z","lastModified":"2026-06-17T10:57:10.000Z","status":"Analyzed","sourceIdentifier":"secteam@freebsd.org","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-121"],"affected":["freebsd/freebsd"],"epss":{"score":0.03431,"percentile":0.88878,"date":"2026-10-27","history":[{"date":"2026-09-24","score":0.01111,"percentile":0.64483},{"date":"2026-10-25","score":0.03431,"percentile":0.88857}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (3.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://security.freebsd.org/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc","tags":["Vendor Advisory"],"source":"secteam@freebsd.org"},{"url":"https://github.com/califio/publications/tree/main/MADBugs/CVE-2026-4747","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/califio/publications/blob/main/MADBugs/CVE-2026-4747/exploit.py","tags":["Exploit"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-4747","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}