Buffer overflow in Wren
CVE-2026-2858
A vulnerability was identified in wren-lang wren up to 0.4.0. This affects the function peekChar of the file src/vm/wren_compiler.c of the component Source File Parser. Such manipulation leads to out-of-bounds read. The attack needs to be performed locally. The exploit is publicly available and might be used. The project was informed of the problem early through an issue report but has not responded yet.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (7.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 7.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Wren
- Wren-Lang Wren — versions 0.1, 0.2, 0.3
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
- github.com/wren-lang/wren/issues/1217 (issue-tracking, Issue Tracking)
- github.com/oneafter/0122/blob/main/i1217/repro (Product, exploit, Issue Tracking)
- github.com/wren-lang/wren/ (Product, product)
Frequently asked questions
- What is CVE-2026-2858?
- CVE-2026-2858 is a low-severity vulnerability in Wren, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 3.3/10. Published 2026-02-20.
- How severe is CVE-2026-2858?
- Low severity. CVSS v3 base score is 3.3 out of 10.