wren-lang wren wren_compiler.c getByteCountForArguments null pointer dereference

published 2026-03-01 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-9122

cvss: 3.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits: 0; none known

A vulnerability has been found in wren-lang wren up to 0.4.0. Affected by this issue is the function getByteCountForArguments of the file src/vm/wren_compiler.c. Such manipulation leads to null pointer dereference. Local access is required to approach this attack. 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.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 8 mo ago (2026-03-02)

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/oneafter/0122/blob/main/i1220/repro referenced PoC, tagged "exploit" by a source, unverified
github.com https://github.com/wren-lang/wren/issues/1220 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	4.8	CVSS: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
CNA	3.1	3.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA	3.0	3.3	CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA	2.0	1.7	AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
CNA	4.0	1.9	CVSS: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
CNA	3.1	3.3	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA	2.0	1.7	AV:L/AC:L/Au:S/C:N/I:N/A:P

Affected products

wren-lang wren

Classification

Weakness

CWE-476 NULL Pointer Dereference
CWE-404 Improper Resource Shutdown or Release

References

github.com /oneafter/0122/blob/main/i1220/repro
exploit
github.com /wren-lang/wren/issues/1220
issue-tracking, exploit, vendor-advisory
vuldb.com /?id.348273
vdb-entry, technical-description, third-party-advisory
vuldb.com /?ctiid.348273
signature, permissions-required, vdb-entry
vuldb.com /?submit.761312
third-party-advisory, vdb-entry
github.com /wren-lang/wren/
product

Sources

CVE List CVE-2026-3387
NVD CVE-2026-3387

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary