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Arm CompilerApplication · Arm

CVE-2020-24658

HIGH · 7.8 CVSS v3.1 Published 2020-12-24
Fix available
A fix is available. Upgrade to 5.06 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Arm Compiler 5 through 5.06u6 has an error in a stack protection feature designed to help spot stack-based buffer overflows in local arrays. When this feature is enabled, a protected function writes a guard value to the stack prior to (above) any vulnerable arrays in the stack. The guard value is checked for corruption on function return; corruption leads to an error-handler call. In certain circumstances, the reference value that is compared against the guard value is itself also written to the stack (after any vulnerable arrays). The reference value is written to the stack when the function runs out of registers to use for other temporary data. If both the reference value and the guard value are written to the stack, then the stack protection will fail to spot corruption when both values are overwritten with the same value. For both the reference value and the guard value to be corrupted, there would need to be both a buffer overflow and a buffer underflow in the vulnerable arrays (or some other vulnerability that causes two separated stack entries to be corrupted).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Arm Compiler 5 through 5.06u6 contains a flaw in its stack protection feature where the reference value used to verify the guard canary is written to the stack after vulnerable arrays when registers are exhausted. If both the guard value and reference value are overwritten with the same value (requiring both buffer overflow and underflow), the stack protection fails to detect the corruption, bypassing this security feature.

MitigationUpgrade to Arm Compiler 5.06u7 or later which contains the fix, or implement additional runtime protections such as address space randomization (ASLR) and process isolation to mitigate potential exploitation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Arm CompilerApplication
Affected:>= 5.01, < 5.06= 5.06

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Arm Compiler 5 version
    Run 'armcc --version' or check the compiler binary path in your build environment to determine the exact version of Arm Compiler 5 installed
    Affected if The version is 5.01 through 5.06u6 (any version < 5.06u7, or exactly 5.06)
  2. Locate build artifacts compiled with Arm Compiler 5
    Review your build logs or project configuration to identify binaries or libraries that were compiled using the affected Arm Compiler 5 version
    Affected if Binaries in your environment were built with a vulnerable Arm Compiler 5 version
  3. Verify stack protection was enabled during compilation
    Check your build configuration or compiler flags for options such as --stack_protection, -fstack-protector, or similar stack canary flags used when compiling the affected binaries
    Affected if Stack protection was enabled (the vulnerability bypasses stack protection, so this feature must be present for the flaw to apply)
  4. Check for overflow/underflow vulnerable code patterns
    Review source code of affected binaries for buffer operations where both overflow (writing past a buffer end) and underflow (writing before buffer start) could occur with the same input, particularly in loops or with register-intensive code paths
    Affected if The compiled code contains arrays where both overflow and underflow could overwrite the same memory region containing the guard canary and its reference value

Your environment is affected if you have binaries compiled with Arm Compiler 5 versions 5.01 through 5.06u6 with stack protection enabled, and those binaries contain code vulnerable to both buffer overflow and underflow that could overwrite the same stack canary region.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 5.06 or later
Fixed in 5.06
Interim mitigation

Upgrade to Arm Compiler 5.06u7 or later which contains the fix, or implement additional runtime protections such as address space randomization (ASLR) and process isolation to mitigate potential exploitation.

Fix this in Arm Compiler Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,000
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-24658 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data