CVE-2026-89533

CVE CVE-2026-89533EUVD EUVD-2026-76439Veröffentlicht 2026-09-11T19:44:12.000ZZuletzt geändert 2026-09-14T12:00:43.000ZCVSS 9.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Fix offset arithmetic in read_chunk_range svc_rdma_read_chunk_range() walks a Read chunk's segment list to build a sub-range starting at byte offset and spanning length bytes for a Position-Zero or Call chunk. Two arithmetic defects in the per-segment loop produce wrong DMA lengths and a u32 underflow: pcl_for_each_segment(segment, chunk) { if (offset > segment->rs_length) { offset -= segment->rs_length; continue; } dummy.rs_handle = segment->rs_handle; dummy.rs_length = min_t(u32, length, segment->rs_length) - offset; dummy.rs_offset = segment->rs_offset + offset; First, the skip predicate uses '>' instead of '>='. When offset equals the segment's full rs_length, the segment is fully consumed and should be skipped, but the loop falls through into the body. The resulting dummy.rs_length is min_t(u32, length, rs_length) - rs_length, which underflows to a near-UINT_MAX u32 when length is smaller than rs_length, or is zero otherwise. Second, the length formula subtracts offset from the min_t() result rather than from segment->rs_length before the cap. For offset > 0 the segment's residual is rs_length - offset, not rs_length, so the cap must be applied to the residual. With the current bracketing, whenever length is smaller than rs_length - offset the per-segment length becomes length - offset instead of length, silently dropping offset bytes from the rebuilt chunk. Combined with the boundary case above it also enables the u32 underflow path, which propagates a huge nr_bvec into svc_rdma_build_read_segment() and a multi-MiB kmalloc_array_node() in svc_rdma_get_rw_ctxt(). Additionally, svc_rdma_read_call_chunk() can invoke this function with length == 0 when the last Read chunk ends exactly at the end of the Call chunk. With the corrected >= predicate, every segment is skipped and the function returns the initial -EINVAL, rejecting a valid request. Return success immediately when length is zero. Also break out of the loop once length is fully consumed to avoid passing zero-length segments to svc_rdma_build_read_segment(). Fix by using '>=' so a fully-consumed segment is skipped, by moving '- offset' inside min_t() so the cap is applied to the segment's residual length, by returning success for zero-length requests, and by stopping iteration when the requested range has been consumed.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4a44c140cc2f3643a39e258bb0c0ab9d0f494f5e; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <a46b35f213c2426f5d6a0458a8f7e873fc59cdfd; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <10873311f91db9454e2fadbf9866bc819e0646d9; patch: 5.15.221; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <cba8543c18cf42fd80fd63effb6df6ff4f7e73ce; patch: 6.1.188; patch: 6.6.157; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <6ee4dc7476b3abc92ec1d444533a559f33f59561; patch: 7.2.4; patch: 7.3-rc1; patch: 0; patch: 6.18.50; patch: 6.12.109; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <4493c96bbd0068fadf69cbae8d13426202e34cdc; d7cc73972661be4a02a1b09f1d9b3283c6c05154 <addbf02dfe3b25e7e38e03bbd4e2a6ed86a14be7; 5.11

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.