high CVSS 7.8

CVE-2020-36788·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: avoid a use-after-free when BO init fails nouveau_bo_init() is backed by ttm_bo_init() and ferries its return code back to the caller. On failures, ttm_bo_init() invokes the provided destructor which should de-initialize and free the memory. Thus, when nouveau_bo_init() returns an error the gem object has already been released and the memory freed by nouveau_bo_del_ttm().

Severity
high
Software
Kernel
Fixed in
5.14.12
Published
2024-05-21

Affected versions

From: 5.11

Until: 5.14.12

Fixed in: 5.14.12

How to fix this CVE

Update your Linux kernel to version 5.14.12 or later to resolve this use-after-free vulnerability in the nouveau GPU driver. The issue occurs when buffer object initialization fails, leaving dangling pointers that can be exploited by local attackers with low privileges. Perform a kernel update followed by a system reboot to apply the patch.

sudo dnf update kernel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Check your current kernel version: uname -r | awk -F'.' '{print $1"."$2"."$3}'
  2. Verify if nouveau driver is loaded: lsmod | grep nouveau
  3. Review dmesg logs for nouveau GPU driver initialization errors: dmesg | grep -i nouveau | grep -i 'error\|fail'
  4. After patching, confirm kernel version is 5.14.12 or higher: uname -r

FAQ

What is CVE-2020-36788?

This is a use-after-free vulnerability in the Linux kernel's nouveau GPU driver that occurs when buffer object initialization fails. An attacker with local access can trigger memory corruption by exploiting the freed but still-referenced GPU memory structures.

Is CVE-2020-36788 being actively exploited?

No, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and no public exploits are currently available.

What versions of Kernel are affected by CVE-2020-36788?

Linux kernel versions 5.11 through 5.14.11 are vulnerable. The patch was included in kernel 5.14.12.

How do I check if my server is vulnerable to CVE-2020-36788?

Run 'uname -r' to see your kernel version. If it shows 5.11.x through 5.14.11, you are vulnerable. Also verify the nouveau driver is in use with 'lsmod | grep nouveau'.

Does Defensia detect CVE-2020-36788?

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-2020-36788 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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.
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-2026-64383CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.
CVE-2026-64385CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
CVE-2026-64384CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix change notify replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_notify_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.

References

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