CVE-2026-4747
A public proof of concept exists; no exploitation attested.
- Published2026-03-26
- WeaknessCWE-121
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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. As 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. In 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.
Timeline
dates in UTC- 2026-03-2607:16CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-4747?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-4747?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 13.5 | = 13.5 | no fix published | NVD |
| 14.3 | = 14.3 | no fix published | NVD |
| 14.4 | = 14.4 | no fix published | NVD |
| 15.0 | = 15.0 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
Advisories and patches
- security.freebsd.orgVendor Advisory
Detection
read 2026-10-23 19:25 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 2 repositories, unverifiedkaleth4/CVE-2026-4747kaleth4/CVE-2026-4747- PoC-in-GitHub
Sources
- NVDCVE recordread 2026-10-23
- CISA-ADPSSVC decisionpoc2026-04-01
- OpenCVESSVC decisionpoc—
- CISA-ADPCVSS 3.18.82026-03-26
- CNAweakness (CWE)CWE-121read 2026-10-23
- FIRST EPSSEPSS score1.2 %2026-10-22
- PoC-in-GitHubproof of concept2read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Published
- 2026-03-26
- Last Modified
- 2026-06-17
- NVD status
- Analyzed
Frequently asked questions
What is CVE-2026-4747?
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What is the CVSS score for CVE-2026-4747?
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