CVE-2026-2858 wren-lang wren Source File wren_compiler.c peekChar out-of-bounds
A local attacker can trigger an out-of-bounds read in the Wren compiler, potentially causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-2858?
CVE-2026-2858 is a medium-severity memory corruption vulnerability in wren-lang wren, published on 20 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-2858?
It affects 1 product.
Products include Wren Wren.
How do I fix CVE-2026-2858?
No fix has been published for CVE-2026-2858 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-2858 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2858 exists.
Other vulnerabilities in wren-lang wren
- CVE-2026-3385 wren-lang wren wren_compiler.c resolveLocal recursion
- CVE-2026-3386 wren-lang wren wren_compiler.c emitOp out-of-bounds
- CVE-2026-3387 wren-lang wren wren_compiler.c getByteCountForArguments null pointer dereference
- CVE-2026-2657 wren-lang wren Error Message wren_compiler.c printError stack-based overflow
Sources
Also known as GHSA-vm4c-6g35-79xf.