CyberSecBulletin
CVE-2022-49945NVD status: Analyzed

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2022-49945 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e9f6972ab40a82bd7f6d36800792ba2e084474d8, 3ff866455e1e263a9ac1958095fd440984248e2f, c8ae6a18708f260ccdeef6ba53af7548457dc26c as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to e9f6972ab40a82bd7f6d36800792ba2e084474d8 or 3ff866455e1e263a9ac1958095fd440984248e2f or c8ae6a18708f260ccdeef6ba53af7548457dc26c or 7756eb1ed124753f4d64f761fc3d84290dffcb4d, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.9.328 or 4.14.293 or 4.19.258 or 5.4.213, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxb5cf88e46badea6d600d8515edea23814e03444d up to, but not including, e9f6972ab40a82bd7f6d36800792ba2e084474d8; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, 3ff866455e1e263a9ac1958095fd440984248e2f; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, c8ae6a18708f260ccdeef6ba53af7548457dc26c; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, 7756eb1ed124753f4d64f761fc3d84290dffcb4d; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, 517dba798793e69b510779c3cde7224a65f3ed1d; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, 53196e0376205ed49b75bfd0475af5e0fbd20156; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, 3263984c7acdcb0658155b05a724ed45a10de76d; b5cf88e46badea6d600d8515edea23814e03444d up to, but not including, f233d2be38dbbb22299192292983037f01ab363c; and 1 more rangese9f6972ab40a82bd7f6d36800792ba2e084474d8, 3ff866455e1e263a9ac1958095fd440984248e2f, c8ae6a18708f260ccdeef6ba53af7548457dc26c, 7756eb1ed124753f4d64f761fc3d84290dffcb4d, 517dba798793e69b510779c3cde7224a65f3ed1d, 53196e0376205ed49b75bfd0475af5e0fbd20156
LinuxLinux Kernel4.1 up to, but not including, 4.9.328; 4.10 up to, but not including, 4.14.293; 4.15 up to, but not including, 4.19.258; 4.20 up to, but not including, 5.4.213; 5.5 up to, but not including, 5.10.142; 5.11 up to, but not including, 5.15.66; 5.16 up to, but not including, 5.19.8; 6.04.9.328, 4.14.293, 4.19.258, 5.4.213, 5.10.142, 5.15.66

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.

Official description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (gpio-fan) Fix array out of bounds access The driver does not check if the cooling state passed to gpio_fan_set_cur_state() exceeds the maximum cooling state as stored in fan_data->num_speeds. Since the cooling state is later used as an array index in set_fan_speed(), an array out of bounds access can occur. This can be exploited by setting the state of the thermal cooling device to arbitrary values, causing for example a kernel oops when unavailable memory is accessed this way. Example kernel oops: [ 807.987276] Unable to handle kernel paging request at virtual address ffffff80d0588064 [ 807.987369] Mem abort info: [ 807.987398] ESR = 0x96000005 [ 807.987428] EC = 0x25: DABT (current EL), IL = 32 bits [ 807.987477] SET = 0, FnV = 0 [ 807.987507] EA = 0, S1PTW = 0 [ 807.987536] FSC = 0x05: level 1 translation fault [ 807.987570] Data abort info: [ 807.987763] ISV = 0, ISS = 0x00000005 [ 807.987801] CM = 0, WnR = 0 [ 807.987832] swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000001165000 [ 807.987872] [ffffff80d0588064] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000 [ 807.987961] Internal error: Oops: 96000005 [#1] PREEMPT SMP [ 807.987992] Modules linked in: cmac algif_hash aes_arm64 algif_skcipher af_alg bnep hci_uart btbcm bluetooth ecdh_generic ecc 8021q garp stp llc snd_soc_hdmi_codec brcmfmac vc4 brcmutil cec drm_kms_helper snd_soc_core cfg80211 snd_compress bcm2835_codec(C) snd_pcm_dmaengine syscopyarea bcm2835_isp(C) bcm2835_v4l2(C) sysfillrect v4l2_mem2mem bcm2835_mmal_vchiq(C) raspberrypi_hwmon sysimgblt videobuf2_dma_contig videobuf2_vmalloc fb_sys_fops videobuf2_memops rfkill videobuf2_v4l2 videobuf2_common i2c_bcm2835 snd_bcm2835(C) videodev snd_pcm snd_timer snd mc vc_sm_cma(C) gpio_fan uio_pdrv_genirq uio drm fuse drm_panel_orientation_quirks backlight ip_tables x_tables ipv6 [ 807.988508] CPU: 0 PID: 1321 Comm: bash Tainted: G C 5.15.56-v8+ #1575 [ 807.988548] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT) [ 807.988574] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 807.988608] pc : set_fan_speed.part.5+0x34/0x80 [gpio_fan] [ 807.988654] lr : gpio_fan_set_cur_state+0x34/0x50 [gpio_fan] [ 807.988691] sp : ffffffc008cf3bd0 [ 807.988710] x29: ffffffc008cf3bd0 x28: ffffff80019edac0 x27: 0000000000000000 [ 807.988762] x26: 0000000000000000 x25: 0000000000000000 x24: ffffff800747c920 [ 807.988787] x23: 000000000000000a x22: ffffff800369f000 x21: 000000001999997c [ 807.988854] x20: ffffff800369f2e8 x19: ffffff8002ae8080 x18: 0000000000000000 [ 807.988877] x17: 0000000000000000 x16: 0000000000000000 x15: 000000559e271b70 [ 807.988938] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 807.988960] x11: 0000000000000000 x10: ffffffc008cf3c20 x9 : ffffffcfb60c741c [ 807.989018] x8 : 000000000000000a x7 : 00000000ffffffc9 x6 : 0000000000000009 [ 807.989040] x5 : 000000000000002a x4 : 0000000000000000 x3 : ffffff800369f2e8 [ 807.989062] x2 : 000000000000e780 x1 : 0000000000000001 x0 : ffffff80d0588060 [ 807.989084] Call trace: [ 807.989091] set_fan_speed.part.5+0x34/0x80 [gpio_fan] [ 807.989113] gpio_fan_set_cur_state+0x34/0x50 [gpio_fan] [ 807.989199] cur_state_store+0x84/0xd0 [ 807.989221] dev_attr_store+0x20/0x38 [ 807.989262] sysfs_kf_write+0x4c/0x60 [ 807.989282] kernfs_fop_write_iter+0x130/0x1c0 [ 807.989298] new_sync_write+0x10c/0x190 [ 807.989315] vfs_write+0x254/0x378 [ 807.989362] ksys_write+0x70/0xf8 [ 807.989379] __arm64_sys_write+0x24/0x30 [ 807.989424] invoke_syscall+0x4c/0x110 [ 807.989442] el0_svc_common.constprop.3+0xfc/0x120 [ 807.989458] do_el0_svc+0x2c/0x90 [ 807.989473] el0_svc+0x24/0x60 [ 807.989544] el0t_64_sync_handler+0x90/0xb8 [ 807.989558] el0t_64_sync+0x1a0/0x1a4 [ 807.989579] Code: b9403801 f9402800 7100003f 8b35cc00 (b9400416) [ 807.989627] ---[ end t ---truncated---

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent Out-of-bounds Read vulnerabilities

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