CyberSecBulletin
CVE-2022-49548NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2022-49548 is a high-severity improper validation of array index vulnerability in Linux, with a CVSS 3.1 base score of 7.8 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 7f845de2863334bed4f362e95853f5e7bc323737, e36452d5da6325df7c10cffc60a9e68d21e2606d, 32c4559c61652f24c9fdd5440342196fe37453bc 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 0.3% 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 7f845de2863334bed4f362e95853f5e7bc323737 or e36452d5da6325df7c10cffc60a9e68d21e2606d or 32c4559c61652f24c9fdd5440342196fe37453bc or 4f8897bcc20b9ae44758e0572538d741ab66f0dc, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.120 or 5.15.45 or 5.17.13 or 5.18.2, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux88fd9e5352fe05f7fe57778293aebd4cd106960b up to, but not including, 7f845de2863334bed4f362e95853f5e7bc323737; 88fd9e5352fe05f7fe57778293aebd4cd106960b up to, but not including, e36452d5da6325df7c10cffc60a9e68d21e2606d; 88fd9e5352fe05f7fe57778293aebd4cd106960b up to, but not including, 32c4559c61652f24c9fdd5440342196fe37453bc; 88fd9e5352fe05f7fe57778293aebd4cd106960b up to, but not including, 4f8897bcc20b9ae44758e0572538d741ab66f0dc; 88fd9e5352fe05f7fe57778293aebd4cd106960b up to, but not including, a2aa95b71c9bbec793b5c5fa50f0a80d882b3e8d; 5.77f845de2863334bed4f362e95853f5e7bc323737, e36452d5da6325df7c10cffc60a9e68d21e2606d, 32c4559c61652f24c9fdd5440342196fe37453bc, 4f8897bcc20b9ae44758e0572538d741ab66f0dc, a2aa95b71c9bbec793b5c5fa50f0a80d882b3e8d
LinuxLinux Kernel5.7 up to, but not including, 5.10.120; 5.11 up to, but not including, 5.15.45; 5.16 up to, but not including, 5.17.13; 5.18 up to, but not including, 5.18.25.10.120, 5.15.45, 5.17.13, 5.18.2

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
HighData or code can be modified at will.
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:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighNVD
CVSS 3.17.8HighCISA (ADP)

Official description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix potential array overflow in bpf_trampoline_get_progs() The cnt value in the 'cnt >= BPF_MAX_TRAMP_PROGS' check does not include BPF_TRAMP_MODIFY_RETURN bpf programs, so the number of the attached BPF_TRAMP_MODIFY_RETURN bpf programs in a trampoline can exceed BPF_MAX_TRAMP_PROGS. When this happens, the assignment '*progs++ = aux->prog' in bpf_trampoline_get_progs() will cause progs array overflow as the progs field in the bpf_tramp_progs struct can only hold at most BPF_MAX_TRAMP_PROGS bpf programs.

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

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Validation of Array Index vulnerabilities

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