medium CVSS 5.5

CVE-2024-38539·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: RDMA/cma: Fix kmemleak in rdma_core observed during blktests nvme/rdma use siw When running blktests nvme/rdma, the following kmemleak issue will appear. kmemleak: Kernel memory leak detector initialized (mempool available:36041) kmemleak: Automatic memory scanning thread started kmemleak: 2 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 8 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 17 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak) unreferenced object 0xffff88855da53400 (size 192): comm "rdma", pid 10630, jiffies 4296575922 hex dump (first 32 bytes): 37 00 00 00 00 00 00 00 c0 ff ff ff 1f 00 00 00 7............... 10 34 a5 5d 85 88 ff ff 10 34 a5 5d 85 88 ff ff .4.].....4.].... backtrace (crc 47f66721): [<ffffffff911251bd>] kmalloc_trace+0x30d/0x3b0 [<ffffffffc2640ff7>] alloc_gid_entry+0x47/0x380 [ib_core] [<ffffffffc2642206>] add_modify_gid+0x166/0x930 [ib_core] [<ffffffffc2643468>] ib_cache_update.part.0+0x6d8/0x910 [ib_core] [<ffffffffc2644e1a>] ib_cache_setup_one+0x24a/0x350 [ib_core] [<ffffffffc263949e>] ib_register_device+0x9e/0x3a0 [ib_core] [<ffffffffc2a3d389>] 0xffffffffc2a3d389 [<ffffffffc2688cd8>] nldev_newlink+0x2b8/0x520 [ib_core] [<ffffffffc2645fe3>] rdma_nl_rcv_msg+0x2c3/0x520 [ib_core] [<ffffffffc264648c>] rdma_nl_rcv_skb.constprop.0.isra.0+0x23c/0x3a0 [ib_core] [<ffffffff9270e7b5>] netlink_unicast+0x445/0x710 [<ffffffff9270f1f1>] netlink_sendmsg+0x761/0xc40 [<ffffffff9249db29>] __sys_sendto+0x3a9/0x420 [<ffffffff9249dc8c>] __x64_sys_sendto+0xdc/0x1b0 [<ffffffff92db0ad3>] do_syscall_64+0x93/0x180 [<ffffffff92e00126>] entry_SYSCALL_64_after_hwframe+0x71/0x79 The root cause: rdma_put_gid_attr is not called when sgid_attr is set to ERR_PTR(-ENODEV).

Severity
medium
Software
Kernel
Fixed in
6.9.3
Published
2024-06-19

Affected versions

From: 6.9

Until: 6.9.3

Fixed in: 6.9.3

How to fix this CVE

Update your Linux kernel to version 6.9.3 or later to resolve a memory leak in the RDMA/CMA subsystem that occurs during NVMe-RDMA operations. The vulnerability causes unreferenced kernel memory allocations that are never freed, potentially leading to memory exhaustion over time. Apply the update immediately if you are running kernel versions 6.9 through 6.9.2 and use RDMA-based storage protocols.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check your kernel version: uname -r | grep -E '^6\.9\.[0-2]' to identify if you are running affected versions (6.9.0 to 6.9.2)
  2. Verify RDMA/CMA modules are loaded: lsmod | grep -i rdma to confirm the vulnerable component is active
  3. Monitor memory leaks during NVMe-RDMA operations: cat /sys/kernel/debug/kmemleak | grep -i 'rdma\|gid' to detect unreferenced memory allocations
  4. After patching, confirm kernel version: uname -r should show 6.9.3 or later, then restart and monitor /sys/kernel/debug/kmemleak for new leaks

FAQ

What is CVE-2024-38539?

CVE-2024-38539 is a kernel memory leak in the RDMA Connection Manager (CMA) subsystem where GID attribute references are not properly released when certain error conditions occur, causing persistent memory waste in systems using NVMe-RDMA storage.

Is CVE-2024-38539 being actively exploited?

No, this vulnerability is not actively exploited in the wild and is not tracked by CISA as a known exploited vulnerability. It is a stability issue rather than a security breach.

What versions of Kernel are affected by CVE-2024-38539?

Linux kernel versions 6.9.0 through 6.9.2 are affected. The vulnerability was fixed in kernel 6.9.3.

How do I check if my server is vulnerable to CVE-2024-38539?

Run 'uname -r' and check if the output matches 6.9.0, 6.9.1, or 6.9.2. If it does and you use RDMA/NVMe storage, your system is vulnerable.

Does Defensia detect CVE-2024-38539?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-38539 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2026-63994CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]() Sashiko found that iptunnel_pmtud_build_icmp() and iptunnel_pmtud_build_icmpv6() were caching ip_hdr() and ipv6_hdr() before an skb_cow() call which can reallocate skb->head. Fix this possible UAF by initializing the local variables after the skb_cow() call. Remove skb_reset_network_header() calls which were not needed.
CVE-2026-64025CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context is present, call psock->saved_data_ready (sock_def_readable) to wake recv() waiters and return immediately, leaving the receive queue untouched. TLS retains sole ownership of the queue and decrypts the record normally through tls_sw_recvmsg().
CVE-2026-100075CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect descriptor, the unwind path destroys RDMA contexts but leaves stale n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending() can then subtract the wrong number of send queue credits. Reset the counters and clear rw_ctxs after freeing the heap allocation before returning an error.
CVE-2026-64000CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: hsr: fix potential OOB access in supervision frame handling Ensure the entire TLV header is linearized before access by adding sizeof(struct hsr_sup_tlv) to the pskb_may_pull() calls. Without this, a truncated frame could cause an out-of-bounds access.
CVE-2026-64439CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion. KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name: BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7 The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site. Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.

References

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