CVE-2023-4039

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

MEDIUM
4.8
CVSS Score
Published: September 13, 2023 at 08:05 AM UTC
Updated: October 14, 2026 at 10:17 PM UTC
2 products affected across 2 vendorsGCCGnu Toolchain

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Severity
MEDIUM4.8
Exploit prediction
EPSS 1%
SSVC
PoC

Description

**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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 2023-09-12, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.8MEDIUMArm
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-693NVD-CWE-Other

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