Bug 2536631 (CVE-2026-90415)

Summary: CVE-2026-90415 kernel: RDMA/cxgb4: free STAG index when TPT entry write fails
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
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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Doc Text:
A flaw was found in the Linux kernel's RDMA/cxgb4 driver. This vulnerability occurs when the system fails to properly free a Steering Tag (STAG) index after an unsuccessful attempt to write to adapter memory. This leads to a resource leak, which could be exploited by a local attacker to cause a denial of service by exhausting available resources.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-17 18:58:20 UTC 
In the Linux kernel, the following vulnerability has been resolved:

RDMA/cxgb4: free STAG index when TPT entry write fails

write_tpt_entry() allocates a new STAG index with c4iw_get_resource() and
bumps stats.stag.cur before programming the entry.  When
write_adapter_mem() fails, it returns the error without releasing the index
or reversing the statistic.  No MR is inserted into rhp->mrs, so
deregistration never reclaims it, leaking the index until device teardown.

Record whether this call allocated the index and, on a failed write, return
it to tpt_table and decrement stats.stag.cur.  Key the rollback on both the
write error and that flag, not the error alone: a non-reset update carries
a caller-owned STAG that this call did not allocate and must not free.
Comment 1 gkamathe 2026-09-21 12:03:28 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90415.mbox