CVE-2026-89674

CVE CVE-2026-89674EUVD EUVD-2026-76586Published 2026-09-11T19:45:58.000ZLast changed 2026-09-14T12:01:59.000ZCVSS 9.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget The XDR buffer size calculation in nfsd4_ff_encode_layoutget() has multiple errors that can result in either an out-of-bounds write or leaking uninitialized kernel memory to the client: - fh_len doesn't account for XDR padding on the file handle data - uid and gid lengths use "8 + len" but xdr_encode_opaque() actually writes "4 + xdr_align_size(len)" bytes - ds_len omits the flags and stats_collect_hint fields (8 bytes), while len's header constant overestimates by 8 bytes -- these partially cancel but leave a net mismatch The worst case occurs with short strings (e.g. uid=0, gid=0 with an odd-sized file handle), where the function writes up to 5 bytes past the reserved XDR buffer. Conversely, when string lengths happen to be 4-byte aligned, the reservation is too large and stale buffer content is sent to the client. Fix this by breaking out every encoded field explicitly in the ds_len calculation, using xdr_align_size() for all variable-length opaque fields, and correcting the header constants.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 6.1.188; patch: 5.10.270; 4.8; 9b9960a0ca4773e21c4b153ed355583946346b25 <c81cef6a805dec266c10fc4f83c93d6fcf1a2b43; patch: 7.2.4; 9b9960a0ca4773e21c4b153ed355583946346b25 <bee826c00ac900473f91306f1f3e5a5a81fd4a74; patch: 6.12.109; 9b9960a0ca4773e21c4b153ed355583946346b25 <29e4478e2ed5a227e8f0c33cacb91bf227cedd47; patch: 5.15.221; 9b9960a0ca4773e21c4b153ed355583946346b25 <e7d9d23ecd9172f05b09bb678ff22db8e361c428; patch: 6.18.50; patch: 0; 9b9960a0ca4773e21c4b153ed355583946346b25 <f9868174af49d207fbaf0c5e055d088a983684af; 9b9960a0ca4773e21c4b153ed355583946346b25 <3a7fd224df0fbb42167eb1b77be45d72fe0b1098; patch: 7.3-rc1; 9b9960a0ca4773e21c4b153ed355583946346b25 <0380129b1373c437eb35401a174671c8888f4b80; patch: 6.6.157; 9b9960a0ca4773e21c4b153ed355583946346b25 <65a72b721943618eeb3a41c8b36e915591f3f83f

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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