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In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix error path fall-through in mlx5_ib_dev_res_srq_init() mlx5_ib_dev_res_srq_init() allocates two SRQs, s0 and s1. When ib_create_srq() fails for s1, the error branch destroys s0 but falls through and unconditionally assigns the freed s0 and the ERR_PTR s1 to devr->s0 and devr->s1. This leads to several problems: the lock-free fast path checks "if (devr->s1) return 0;" and treats the ERR_PTR as already initialised; users in mlx5_ib_create_qp() dereference the freed SRQ or ERR_PTR via to_msrq(devr->s0)->msrq.srqn; and mlx5_ib_dev_res_cleanup() dereferences the ERR_PTR and double-frees s0 on teardown. Fix by adding the same `goto unlock` in the s1 failure path.
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2026052828-CVE-2026-46176-a4db@gregkh/T
Exploitation Scenarios 1. Use-After-Free Exploitation: - Attacker triggers SRQ creation failure for s1 - Freed s0 memory is reallocated for attacker-controlled data - Subsequent mlx5_ib_create_qp() call dereferences attacker-controlled memory - Potential for arbitrary code execution or privilege escalation 2. Double-Free Exploitation: - During teardown, mlx5_ib_dev_res_cleanup() attempts to free already-freed s0 - Can lead to heap corruption - Exploitable for denial of service or memory corruption attacks 3. Denial of Service: - Simpler attack: repeatedly trigger the vulnerability to crash the kernel - No special exploitation techniques required - System becomes unavailable
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:30848 https://access.redhat.com/errata/RHSA-2026:30848
This issue has been addressed in the following products: Red Hat Enterprise Linux 10.0 Extended Update Support Via RHSA-2026:33215 https://access.redhat.com/errata/RHSA-2026:33215
This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:33685 https://access.redhat.com/errata/RHSA-2026:33685
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.6 Extended Update Support Via RHSA-2026:34094 https://access.redhat.com/errata/RHSA-2026:34094