Cyber Resilience

CVE-2026-2657

Memory Safety in Wren ≤ 0.4.0

Public PoCMemory Safety
Published
18 February 2026
Modified
20 February 2026
Patch / advisory
CVSS Score v4 4.8
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0025 16th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-2657 is a medium-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Wren Wren. Its CVSS base score is 4.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 16th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-16 (Memory Protection) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability has been found in wren-lang wren up to 0.4.0. This impacts the function printError of the file src/vm/wren_compiler.c of the component Error Message Handler. Such manipulation leads to stack-based buffer overflow. An attack has to be approached locally.…

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The exploit has been disclosed to the public and may be used. The project was informed of the problem early through an issue report but has not responded yet.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Local stack-based buffer overflow directly enables exploitation for privilege escalation via arbitrary code execution in the error handler.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-3386Same product: Wren Wren
CVE-2026-2858Same product: Wren Wren
CVE-2026-3810Shared CWE-119, CWE-121
CVE-2025-4892Shared CWE-119, CWE-121
CVE-2026-10528Shared CWE-119, CWE-121
CVE-2026-13573Shared CWE-119, CWE-121
CVE-2025-8845Shared CWE-119, CWE-121
CVE-2026-5991Shared CWE-119, CWE-121
CVE-2026-5037Shared CWE-119, CWE-121
CVE-2026-14605Shared CWE-119, CWE-121

Affected Assets

wren
wren
≤ 0.4.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-16 Memory Protection
  • SC-39 Process Isolation
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V17.3.2

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly prevents the stack buffer overflow by validating all input to the printError function before string formatting occurs.

prevent

Applies memory protection mechanisms (e.g., stack canaries, ASLR, NX) that block exploitation of the CWE-121 flaw in wren_compiler.c.

prevent

Process isolation limits the blast radius of a successful local stack overflow to the wren VM process only.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (bounds checking, safe APIs, reviews) directly prevent this class of flaw.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

prevents

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

prevents

Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.

none

Change-management gates can enforce security reviews that catch buffer issues.

References