CVE-2026-53398 NFSD: Fix SECINFO_NO_NAME decode error cleanup
A flaw in the Linux kernel NFSD component allows a denial of service via improper cleanup of uninitialized variables during truncated XDR decoding.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53398?
CVE-2026-53398 is a critical vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
NFSD: Fix SECINFO_NO_NAME decode error cleanup
nfsd4_decode_secinfo_no_name() currently initializes sin_exp after decoding sin_style. If the XDR stream is truncated, the decoder returns nfserr_bad_xdr before sin_exp is initialized.
Since commit 3fdc54646234 ("NFSD: Reduce amount of struct nfsd4_compoundargs that needs clearing"), the inline iops array is not cleared between RPC calls. A failed SECINFO_NO_NAME decode can therefore leave sin_exp holding stale union contents from a previous operation.
The error response path still invokes nfsd4_secinfo_no_name_release(), which calls exp_put() on a non-NULL sin_exp.
Initialize sin_exp before the first failable decode step, matching nfsd4_decode_secinfo().
Weakness: CWE-665
Which versions are affected by CVE-2026-53398?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53398?
Apply the vendor's patch.
Is CVE-2026-53398 being exploited?
There is no known exploitation of CVE-2026-53398 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-53398, DEBIAN-CVE-2026-53398, GHSA-hfvv-wwwp-6wgr, ROOT-OS-DEBIAN-11-CVE-2026-53398, ROOT-OS-UBUNTU-2204-CVE-2026-53398, UBUNTU-CVE-2026-53398.