CVE-2026-80985 net/smc: carry oversized SMC-Rv2 LLC messages in the queue entry
A remote attacker can corrupt memory and delete or install arbitrary rkeys in the Linux kernel SMC module by sending oversized LLC messages.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80985?
CVE-2026-80985 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net/smc: carry oversized SMC-Rv2 LLC messages in the queue entry
smc_llc_rmt_delete_rkey() and smc_llc_save_add_link_rkeys() read the part of a v2 message that does not fit into the 44-byte union smc_llc_msg, and both bound themselves by the size of the buffer it landed in, not by what arrived. On a link with a shared v2 receive buffer a 44-byte DELETE_RKEY_V2 declaring 255 rkeys reaches rkey[9..254] in whatever an earlier message left in lgr->wr_rx_buf_v2, and passes each of them to smc_rtoken_delete(). One of those 255 matched a registered rtoken and deleted it. An ADD_LINK on such a link installs up to 255 rtokens from the same bytes.
Copy the tail into the queue entry, so its length is the length of the message that arrived, and declare the rkeys that fit inline as a member of the union instead of reaching them through a cast. The same DELETE_RKEY_V2 now processes the 9 rkeys it carries. The copy is limited to the longest tail the two functions can read, so the peer does not pick the size of the entry.
The bound the previous patch placed on links without a shared v2 receive buffer is no longer needed.
Which versions are affected by CVE-2026-80985?
How do I fix CVE-2026-80985?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-80985 being exploited?
There is no known exploitation of CVE-2026-80985 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80985, DEBIAN-CVE-2026-80985, GHSA-439p-4phc-pprq, UBUNTU-CVE-2026-80985.