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Integer Underflow Affecting kernel-zfcpdump-modules-extra package, versions *

Severity

 Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.51% (42nd percentile)

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  • Snyk IDSNYK-CENTOS10-KERNELZFCPDUMPMODULESEXTRA-19805824
  • published15 Sept 2026
  • disclosed11 Sept 2026
Report a new vulnerability Found a mistake?

Introduced: 11 Sep 2026

NewCVE-2026-89533  (opens in a new tab)
CWE-191  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-zfcpdump-modules-extra.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-modules-extra package and not the kernel-zfcpdump-modules-extra package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1