CVE-2022-49261
Published: 26 February 2025
Summary
CVE-2022-49261 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 7.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2022-49261 is a vulnerability in the Linux kernel's Direct Rendering Manager (DRM) i915 GEM subsystem, specifically in the vm_access() function. The issue stems from a missing bounds check on the len parameter before a memcpy operation, which can result in out-of-bounds reads or writes into adjacent kernel memory areas. This flaw was demonstrated by a proof-of-concept that triggered a kernel page fault and oops during a supervisor read access, as seen in the provided kernel crash log from a tainted 5.17.0-rc6 kernel on Intel CoffeeLake hardware.
A local attacker with low privileges (PR:L) can exploit this vulnerability with low complexity (AC:L) and no user interaction required. Exploitation occurs through operations like vfs_read on an i915-related interface, such as __access_remote_vm leading to mem_rw. Successful exploitation enables high confidentiality, integrity, and availability impacts (CVSS 7.8: C:H/I:H/A:H), potentially allowing arbitrary kernel memory corruption, information disclosure, or denial of service via kernel crashes, as evidenced by the memcpy_erms fault in the trace.
Mitigation involves applying the relevant stable kernel patches, such as those in commits 312d3d4f49e12f97260bcf972c848c3562126a18, 3886a86e7e6cc6ce2ce93c440fecd8f42aed0ce7, 5f6e560e3e86ac053447524224e411034f41f5c7, 89ddcc81914ab58cc203acc844f27d55ada8ec0e, and 8f0ebea8f6e8c474264ed97d7a64c9c09ed4f5f5aa from git.kernel.org/stable. These patches add the missing boundary check using range_overflows_t and were cherry-picked from upstream commit 661412e301e2ca86799aa4f400d1cf0bd38c57c6. Security practitioners should ensure systems with i915 drivers update to kernels incorporating these fixes.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2022-54965
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: drm/i915/gem: add missing boundary check in vm_access A missing bounds check in vm_access() can lead to an out-of-bounds read or write in the adjacent memory area, since the len attribute…
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is not validated before the memcpy later in the function, potentially hitting: [ 183.637831] BUG: unable to handle page fault for address: ffffc90000c86000 [ 183.637934] #PF: supervisor read access in kernel mode [ 183.637997] #PF: error_code(0x0000) - not-present page [ 183.638059] PGD 100000067 P4D 100000067 PUD 100258067 PMD 106341067 PTE 0 [ 183.638144] Oops: 0000 [#2] PREEMPT SMP NOPTI [ 183.638201] CPU: 3 PID: 1790 Comm: poc Tainted: G D 5.17.0-rc6-ci-drm-11296+ #1 [ 183.638298] Hardware name: Intel Corporation CoffeeLake Client Platform/CoffeeLake H DDR4 RVP, BIOS CNLSFWR1.R00.X208.B00.1905301319 05/30/2019 [ 183.638430] RIP: 0010:memcpy_erms+0x6/0x10 [ 183.640213] RSP: 0018:ffffc90001763d48 EFLAGS: 00010246 [ 183.641117] RAX: ffff888109c14000 RBX: ffff888111bece40 RCX: 0000000000000ffc [ 183.642029] RDX: 0000000000001000 RSI: ffffc90000c86000 RDI: ffff888109c14004 [ 183.642946] RBP: 0000000000000ffc R08: 800000000000016b R09: 0000000000000000 [ 183.643848] R10: ffffc90000c85000 R11: 0000000000000048 R12: 0000000000001000 [ 183.644742] R13: ffff888111bed190 R14: ffff888109c14000 R15: 0000000000001000 [ 183.645653] FS: 00007fe5ef807540(0000) GS:ffff88845b380000(0000) knlGS:0000000000000000 [ 183.646570] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 183.647481] CR2: ffffc90000c86000 CR3: 000000010ff02006 CR4: 00000000003706e0 [ 183.648384] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 183.649271] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 183.650142] Call Trace: [ 183.650988] <TASK> [ 183.651793] vm_access+0x1f0/0x2a0 [i915] [ 183.652726] __access_remote_vm+0x224/0x380 [ 183.653561] mem_rw.isra.0+0xf9/0x190 [ 183.654402] vfs_read+0x9d/0x1b0 [ 183.655238] ksys_read+0x63/0xe0 [ 183.656065] do_syscall_64+0x38/0xc0 [ 183.656882] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 183.657663] RIP: 0033:0x7fe5ef725142 [ 183.659351] RSP: 002b:00007ffe1e81c7e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [ 183.660227] RAX: ffffffffffffffda RBX: 0000557055dfb780 RCX: 00007fe5ef725142 [ 183.661104] RDX: 0000000000001000 RSI: 00007ffe1e81d880 RDI: 0000000000000005 [ 183.661972] RBP: 00007ffe1e81e890 R08: 0000000000000030 R09: 0000000000000046 [ 183.662832] R10: 0000557055dfc2e0 R11: 0000000000000246 R12: 0000557055dfb1c0 [ 183.663691] R13: 00007ffe1e81e980 R14: 0000000000000000 R15: 0000000000000000 Changes since v1: - Updated if condition with range_overflows_t [Chris Wilson] [mauld: tidy up the commit message and add Cc: stable] (cherry picked from commit 661412e301e2ca86799aa4f400d1cf0bd38c57c6)
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Missing bounds check in kernel DRM i915 vm_access enables local memory corruption for privilege escalation via arbitrary kernel read/write.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Applying kernel patches that add the missing boundary check in vm_access() directly remediates the out-of-bounds read/write vulnerability.
Validating the 'len' parameter bounds before memcpy in the i915 GEM vm_access() function prevents out-of-bounds memory access by untrusted inputs.
Kernel memory protections such as guard pages and address space isolation mitigate exploitation of out-of-bounds accesses into adjacent memory areas.