Linux Kernel SMC LLC qentry overwrite causes kmalloc-96 memory leak
CVE-2026-74719 Published on August 22, 2026
net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler()
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler()
The SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT branch in
smc_llc_event_handler() stores an incoming qentry into the local LLC flow
without first checking whether a qentry is already pending. If a malicious or
buggy peer sends a second CONFIRM_LINK or ADD_LINK_CONT request while a flow is
active and flow->qentry is already set, smc_llc_flow_qentry_set() overwrites the
pointer without freeing the previous allocation, leaking one kmalloc-96 object
per spurious message.
The sibling SMC_LLC_DELETE_LINK branch already has the correct !flow->qentry
guard. Apply the same guard to the CONFIRM_LINK/ADD_LINK_CONT branch so that a
duplicate message when qentry is already occupied falls through to break and is
freed by the kfree(qentry) at the out: label, rather than silently leaking the
existing allocation.
The response direction (smc_llc_rx_response()) is unaffected: it already guards
with flow->qentry at the equivalent site and drops duplicate responses
correctly.
Products Associated with CVE-2026-74719
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Affected Versions
Linux:- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below e384f3cba6ea709f5b2272b1770db4ce14047f78 is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below a1e980d7a9e7ee6faf4f5fd7b450413b969af26d is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below e0eb87677c76b157cdf8eb7c1f19e56227165a33 is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below 06734dfeaeba886aab1bf147249195b888ac3e4d is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below c23c409228629107203d3c3e95fff1473173f1a6 is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below 10cb31b2b74cb664c6c95cf72364d7d5c483ab82 is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below bfc336a9fbbf09805f3dfe25c195a4db90af2846 is affected.
- Version 0fb0b02bd6fd26cba38002be4a6bbcae2228fd44 and below 976245094925bab9bc39366b2e9ab44ffcde61d0 is affected.
- Version 5.8 is affected.
- Before 5.8 is unaffected.
- Version 5.10.265, <= 5.10.* is unaffected.
- Version 5.15.216, <= 5.15.* is unaffected.
- Version 6.1.183, <= 6.1.* is unaffected.
- Version 6.6.152, <= 6.6.* is unaffected.
- Version 6.12.104, <= 6.12.* is unaffected.
- Version 6.18.45, <= 6.18.* is unaffected.
- Version 7.1.9, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.