Bug 2546427 (CVE-2026-98298)

Summary: CVE-2026-98298 kernel: dmaengine: mmp_pdma: fix wrong sg length in mmp_pdma_prep_slave_sg()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's MMP Peripheral Direct Memory Access (PDMA) driver. When preparing multi-entry scatter-gather lists for Direct Memory Access (DMA) transfers, the driver incorrectly reads the buffer length from the initial list entry rather than the active entry being processed. A local user could exploit this flaw to trigger out-of-bounds memory reads, leading to system crashes or potential information disclosure, or cause silent data loss during DMA operations.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-06 09:19:21 UTC
In the Linux kernel, the following vulnerability has been resolved:

dmaengine: mmp_pdma: fix wrong sg length in mmp_pdma_prep_slave_sg()

In mmp_pdma_prep_slave_sg(), for_each_sg() iterates the scatterlist
putting each entry into 'sg', but the entry length is read from 'sgl'
(the list head) instead of 'sg' (the current entry):

    for_each_sg(sgl, sg, sg_len, i) {
        addr = sg_dma_address(sg);
        avail = sg_dma_len(sgl);   /* should be 'sg' */

Consequently 'avail' is always the length of the first entry. For
multi-sg lists this causes out-of-bounds reads when a later entry is
shorter than the first, and silent data loss when it is longer.
Single-sg or uniformly-sized lists happen to mask the issue.