Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix READDIR buffer overflow If a client sends a READDIR count argument that is too small (say, zero), then the buffer size calculation in the new init_dirlist helper functions results in an underflow, allowing the XDR stream functions to write beyond the actual buffer. This calculation has always been suspect. NFSD has never sanity- checked the READDIR count argument, but the old entry encoders managed the problem correctly. With the commits below, entry encoding changed, exposing the underflow to the pointer arithmetic in xdr_reserve_space(). Modern NFS clients attempt to retrieve as much data as possible for each READDIR request. Also, we have no unit tests that exercise the behavior of READDIR at the lower bound of @count values. Thus this case was missed during testing.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.13, < 5.15.12 |
Related Weaknesses (CWE)
References
- https://git.kernel.org/stable/c/53b1119a6e5028b125f431a0116ba73510d82a72ExploitMailing ListPatch
- https://git.kernel.org/stable/c/9e291a6a28d32545ed2fd959a8165144d1724df1ExploitMailing ListPatch
- https://git.kernel.org/stable/c/eabc0aab98e5218ceecd82069b0d6fdfff5ee885ExploitMailing ListPatch
- https://git.kernel.org/stable/c/53b1119a6e5028b125f431a0116ba73510d82a72ExploitMailing ListPatch
- https://git.kernel.org/stable/c/9e291a6a28d32545ed2fd959a8165144d1724df1ExploitMailing ListPatch
- https://git.kernel.org/stable/c/eabc0aab98e5218ceecd82069b0d6fdfff5ee885ExploitMailing ListPatch
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
FAQ
What is CVE-2021-47107?
CVE-2021-47107 is a vulnerability with a CVSS score of 7.8 (HIGH). In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix READDIR buffer overflow If a client sends a READDIR count argument that is too small (say, zero), then the buffer size c...
How severe is CVE-2021-47107?
CVE-2021-47107 has been rated HIGH with a CVSS base score of 7.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-47107?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.