svcrdma: Fix pcl_for_each_segment for empty chunks
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Fix pcl_for_each_segment for empty chunks When a parsed chunk list contains a chunk whose ch_segcount is zero, pcl_for_each_segment computes its inclusive upper bound as &chunk->ch_segments[ch_segcount - 1]. ch_segcount is u32, so the subtraction wraps to 0xFFFFFFFF and the bound lands far past the ch_segments flex array. The loop body then walks unrelated memory at sizeof(struct svc_rdma_segment) stride until it faults. A zero-segcount chunk is reachable from the wire: xdr_check_write_chunk() only rejects segcount values greater than rc_maxpages, and pcl_alloc_write() links a freshly allocated chunk onto rc_write_pcl/rc_reply_pcl before its segment-fill loop runs, so a Write or Reply chunk advertising zero segments leaves ch_segcount == 0 on the list. When the transport has negotiated Send-With-Invalidate, svc_rdma_get_inv_rkey() iterates all four PCLs with pcl_for_each_segment and dereferences segment->rs_handle on each iteration, turning the underflow into an out-of-bounds read and a general protection fault. xdr_check_write_list / xdr_check_reply_chunk pcl_alloc_write() chunk = pcl_alloc_chunk(...) /* ch_segcount = 0 */ list_add_tail(&chunk->ch_list, &pcl->cl_chunks) /* fill loop iterates zero times for wire segcount 0 */ svc_rdma_get_inv_rkey() pcl_for_each_chunk(rc_write_pcl) pcl_for_each_segment(segment, chunk) pos <= &ch_segments[0u - 1u] /* 0xFFFFFFFF */ segment->rs_handle /* OOB read -> GPF
CVE-2026-89532
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89532
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "1e2e3481e39103a386b86be1c33eaef97cbdf16e",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "3a78b841879c2a3243f74edc514236fb2907167f",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "06d0390c37fa6714624af771bd72bbf1a7ed9bb1",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "9c5a03c3dc505c0295339b0a1b9e4fe36447e482",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "a1c954ca4977a4e6ec73ef92fe48073ec54f9fc8",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "6d33a7e6bf6c6b293a266a617201285a1ad32c56",
"versionType": "git"
},
{
"status": "affected",
"version": "78147ca8b4a9b6cf0e597ddd6bf17959e08376c2",
"lessThan": "b7713a784c59515d0aba558c8f5df6a0164dd3a9",
"versionType": "git"
}
],
"programFiles": [
"include/linux/sunrpc/svc_rdma_pcl.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/linux/sunrpc/svc_rdma_pcl.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89532
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #35053 · Revision 1
- Added to Heist Feed
- Publisher date