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Vulnerabilities

Vulnerability · CVE-2023-4039

GCC's-fstack-protector fails to guard dynamically-sized local variables on AArch64

Published Sep 13, 2023 · catalog updated Oct 14, 2026 · Arm Ltd Arm GNU Toolchain

Check if you run it

No confirmed exploitation is on record for CVE-2023-4039. EPSS is 1.04%. Act only if a listed version of Arm Ltd Arm GNU Toolchain is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium4.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.04%
Remediation
Advisory link
Affected products
cpe gnu/gcc · vendor Arm Ltd Arm GNU Toolchain · vendor GNU GCC

**DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains that target AArch64 allows an attacker to exploit an existing buffer overflow in dynamically-sized local variables in your application without this being detected. This stack-protector failure only applies to C99-style dynamically-sized local variables or those created using alloca(). The stack-protector operates as intended for statically-sized local variables. The default behavior when the stack-protector detects an overflow is to terminate your application, resulting in controlled loss of availability. An attacker who can exploit a buffer overflow without triggering the stack-protector might be able to change program flow control to cause an uncontrolled loss of availability or to go further and affect confidentiality or integrity. NOTE: The GCC project argues that this is a missed hardening bug and not a vulnerability by itself.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe gnu/gccversion unspecified
  • vendor Arm Ltd Arm GNU Toolchainversion unspecified
  • vendor GNU GCCversion unspecified

How to fix CVE-2023-4039

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2023-4039. EPSS is 1.04%. Act only if a listed version of Arm Ltd Arm GNU Toolchain is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-693: Protection Mechanism Failure. EPSS 1.04%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 13, 2023 · NIST NVD

    Detected

    **DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains that target AArch64 allows an attacker to exploit an existing buffer overflow in dynamically-sized local variables in your application without this being detected. This stack-protector failure only applies to C99-style dynamically-sized local variables or those created using alloca(). The stack-protector operates as int

  2. Oct 14, 2026 · NIST NVD

    Updated

    **DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains that target AArch64 allows an attacker to exploit an existing buffer overflow in dynamically-sized local variables in your application without this being detected. This stack-protector failure only applies to C99-style dynamically-sized local variables or those created using alloca(). The stack-protector operates as int

Sources

  • CIRCL Vulnerability LookupVulnerability recordCVE-2023-4039

    **DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains that target AArch64 allows an attacker to exploit an existing buffer overflow in dynamically-sized local variables in your application without this being detected. This stack-protector failure only app

    vulnerability.circl.lu
  • CVE.orgVulnerability recordCVE-2023-4039

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-4039

    30-day exploitation probability 1.0%

    first.org
  • NIST NVDVulnerability recordCVE-2023-4039

    **DISPUTED**A failure in the -fstack-protector feature in GCC-based toolchains that target AArch64 allows an attacker to exploit an existing buffer overflow in dynamically-sized local variables in your application without this being detected. This stack-protector failure only

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.