CVE-2026-74719

Description

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.

References

• https://git.kernel.org/stable/c/06734dfeaeba886aab1bf147249195b888ac3e4d
• https://git.kernel.org/stable/c/10cb31b2b74cb664c6c95cf72364d7d5c483ab82
• https://git.kernel.org/stable/c/976245094925bab9bc39366b2e9ab44ffcde61d0
• https://git.kernel.org/stable/c/a1e980d7a9e7ee6faf4f5fd7b450413b969af26d
• https://git.kernel.org/stable/c/bfc336a9fbbf09805f3dfe25c195a4db90af2846