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Linux Kernel CVE-2025-38449

MEDIUM
Use After Free (CWE-416)
2025-07-25 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Information Disclosure Linux Use After Free Memory Corruption Red Hat Suse
5.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.5 MEDIUM

Local access with DRM group membership required (PR:L, AV:L); kernel crash is availability-only with no confidentiality or integrity impact.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
6.6 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Red Hat
7.3 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Analysis Generated
Jul 30, 2026 - 08:49 vuln.today
CVE Published
Jul 25, 2025 - 16:15 nvd
MEDIUM 5.5

DescriptionNVD

In the Linux kernel, the following vulnerability has been resolved:

drm/gem: Acquire references on GEM handles for framebuffers

A GEM handle can be released while the GEM buffer object is attached to a DRM framebuffer. This leads to the release of the dma-buf backing the buffer object, if any. [1] Trying to use the framebuffer in further mode-setting operations leads to a segmentation fault. Most easily happens with driver that use shadow planes for vmap-ing the dma-buf during a page flip. An example is shown below.

[ 156.791968] ------------[ cut here ]------------ [ 156.796830] WARNING: CPU: 2 PID: 2255 at drivers/dma-buf/dma-buf.c:1527 dma_buf_vmap+0x224/0x430 [...] [ 156.942028] RIP: 0010:dma_buf_vmap+0x224/0x430 [ 157.043420] Call Trace: [ 157.045898] <TASK> [ 157.048030] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.052436] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.056836] ? show_trace_log_lvl+0x1af/0x2c0 [ 157.061253] ? drm_gem_shmem_vmap+0x74/0x710 [ 157.065567] ? dma_buf_vmap+0x224/0x430 [ 157.069446] ? __warn.cold+0x58/0xe4 [ 157.073061] ? dma_buf_vmap+0x224/0x430 [ 157.077111] ? report_bug+0x1dd/0x390 [ 157.080842] ? handle_bug+0x5e/0xa0 [ 157.084389] ? exc_invalid_op+0x14/0x50 [ 157.088291] ? asm_exc_invalid_op+0x16/0x20 [ 157.092548] ? dma_buf_vmap+0x224/0x430 [ 157.096663] ? dma_resv_get_singleton+0x6d/0x230 [ 157.101341] ? __pfx_dma_buf_vmap+0x10/0x10 [ 157.105588] ? __pfx_dma_resv_get_singleton+0x10/0x10 [ 157.110697] drm_gem_shmem_vmap+0x74/0x710 [ 157.114866] drm_gem_vmap+0xa9/0x1b0 [ 157.118763] drm_gem_vmap_unlocked+0x46/0xa0 [ 157.123086] drm_gem_fb_vmap+0xab/0x300 [ 157.126979] drm_atomic_helper_prepare_planes.part.0+0x487/0xb10 [ 157.133032] ? lockdep_init_map_type+0x19d/0x880 [ 157.137701] drm_atomic_helper_commit+0x13d/0x2e0 [ 157.142671] ? drm_atomic_nonblocking_commit+0xa0/0x180 [ 157.147988] drm_mode_atomic_ioctl+0x766/0xe40 [...] [ 157.346424] ---[ end trace 0000000000000000 ]---

Acquiring GEM handles for the framebuffer's GEM buffer objects prevents this from happening. The framebuffer's cleanup later puts the handle references.

Commit 1a148af06000 ("drm/gem-shmem: Use dma_buf from GEM object instance") triggers the segmentation fault easily by using the dma-buf field more widely. The underlying issue with reference counting has been present before.

v2:

  • acquire the handle instead of the BO (Christian)
  • fix comment style (Christian)
  • drop the Fixes tag (Christian)
  • rename err_ gotos
  • add missing Link tag

AnalysisAI

Use-after-free in the Linux kernel's DRM/GEM graphics subsystem allows a local user to crash the kernel by prematurely releasing a GEM handle while its buffer object remains attached to a DRM framebuffer, freeing the underlying dma-buf. Drivers using shadow planes to vmap the dma-buf during page flips (notably drm_gem_shmem-based drivers) then dereference the freed pointer during mode-setting, producing a kernel OOPS or WARNING and a denial of service. No public exploit or CISA KEV listing exists at time of analysis; EPSS at 0.15% (4th percentile) confirms exploitation is rare and targeted rather than opportunistic.

Technical ContextAI

The DRM (Direct Rendering Manager) subsystem manages GPU resources through the GEM (Graphics Execution Manager) framework. GEM handles are per-process integer references to underlying GEM buffer objects; closing a handle decrements the object's reference count. When a GEM buffer object is exported as a dma-buf (DMA buffer sharing interface, used for zero-copy cross-subsystem sharing), releasing its GEM handle without first pinning a reference on behalf of the framebuffer frees the dma-buf prematurely. CWE-416 (Use After Free) manifests when the DRM atomic commit path calls drm_gem_fb_vmap → drm_gem_vmap → drm_gem_shmem_vmap → dma_buf_vmap on the now-freed dma-buf pointer. The fix acquires GEM handle references when building framebuffers, ensuring the framebuffer teardown path releases them rather than userspace handle closure. The issue predates but was made trivially reproducible by commit 1a148af06000 ('drm/gem-shmem: Use dma_buf from GEM object instance'), which widened dma-buf field usage. Affected CPE: cpe:2.3:o:linux:linux_kernel including 6.16-rc1 through 6.16-rc4.

RemediationAI

Apply the four upstream stable-tree patches from kernel.org: 08480e285c6a (https://git.kernel.org/stable/c/08480e285c6a82ce689008d643e4a51db0aaef8b), 3cf520d9860d (https://git.kernel.org/stable/c/3cf520d9860d4ec9f7f32068825da31f18dd3f25), 5307dce878d4 (https://git.kernel.org/stable/c/5307dce878d4126e1b375587318955bd019c3741), and cb4c956a15f8 (https://git.kernel.org/stable/c/cb4c956a15f8b7f870649454771fc3761f504b5f). Distribution users should apply kernel updates as they are released by their vendor. As a compensating control prior to patching, restrict unprivileged access to DRM device nodes by removing non-essential users from the 'video' and 'render' groups, or apply udev rules to tighten permissions on /dev/dri/* to root-only - this eliminates the attack surface at the cost of disabling GPU/display access for those accounts. On headless servers with no DRM device nodes accessible to unprivileged users, no additional action is required beyond routine kernel update hygiene.

Same weakness CWE-416 – Use After Free

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
Container suse/hpc/warewulf4-x86_64/sle-hpc-node:15.6.17.8.103 Image SLES15-SP6 Image SLES15-SP6-BYOS Image SLES15-SP6-BYOS-Azure Image SLES15-SP6-BYOS-EC2 Image SLES15-SP6-BYOS-GCE Image SLES15-SP6-CHOST-BYOS Image SLES15-SP6-CHOST-BYOS-Aliyun Image SLES15-SP6-CHOST-BYOS-Azure Image SLES15-SP6-CHOST-BYOS-EC2 Image SLES15-SP6-CHOST-BYOS-GCE Image SLES15-SP6-CHOST-BYOS-GDC Image SLES15-SP6-CHOST-BYOS-SAP-CCloud Image SLES15-SP6-EC2 Image SLES15-SP6-EC2-ECS-HVM Image SLES15-SP6-GCE Image SLES15-SP6-HPC-BYOS Image SLES15-SP6-HPC-BYOS-Azure Image SLES15-SP6-HPC-BYOS-EC2 Image SLES15-SP6-HPC-BYOS-GCE Image SLES15-SP6-HPC-EC2 Image SLES15-SP6-HPC-GCE Image SLES15-SP6-Hardened-BYOS Image SLES15-SP6-Hardened-BYOS-Azure Image SLES15-SP6-Hardened-BYOS-EC2 Image SLES15-SP6-Hardened-BYOS-GCE Image SLES15-SP6-SAP Image SLES15-SP6-SAP-Azure Image SLES15-SP6-SAP-EC2 Image SLES15-SP6-SAP-GCE Image SLES15-SP6-SAPCAL Image SLES15-SP6-SAPCAL-Azure Image SLES15-SP6-SAPCAL-EC2 Image SLES15-SP6-SAPCAL-GCE Affected
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.44 Container suse/sl-micro/6.1/base-os-container:2.2.1-5.27 Image SL-Micro Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SLE-Micro Image SLE-Micro-Azure Image SLE-Micro-BYOS Image SLE-Micro-BYOS-Azure Image SLE-Micro-BYOS-EC2 Image SLE-Micro-BYOS-GCE Image SLE-Micro-EC2 Image SLE-Micro-GCE Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected
Container suse/sl-micro/6.0/kvm-os-container:2.1.3-6.67 Container suse/sl-micro/6.1/kvm-os-container:2.2.1-5.29 Affected
Container suse/sl-micro/6.0/rt-os-container:2.1.3-7.76 Container suse/sl-micro/6.1/rt-os-container:2.2.1-5.14 Affected
Image SLES-Azure-3P Image SLES-Azure-Basic Image SLES-Azure-Standard Image SLES-BYOS-Azure Image SLES-BYOS-EC2 Image SLES-BYOS-GCE Image SLES-CHOST-BYOS-Aliyun Image SLES-CHOST-BYOS-Azure Image SLES-CHOST-BYOS-EC2 Image SLES-CHOST-BYOS-GCE Image SLES-CHOST-BYOS-GDC Image SLES-CHOST-BYOS-SAP-CCloud Image SLES-EC2 Image SLES-EC2-ECS Image SLES-GCE Image SLES-GCE-3P Image SLES-Hardened-BYOS-Azure Image SLES-Hardened-BYOS-EC2 Image SLES-Hardened-BYOS-GCE Image SLES-SAPCAL-Azure Image SLES-SAPCAL-EC2 Image SLES-SAPCAL-GCE Affected

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CVE-2025-38449 vulnerability details – vuln.today
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