CVE-2026-2858Public exploit

Process crash via unterminated raw string scan

Published Feb 20, 2026 · Updated Feb 20, 2026

Out-of-bounds read in Wren 0.4.0 and earlier allows local users to crash an embedding process via malformed raw string syntax. In src/vm/wren_compiler.c, readRawString repeatedly calls peekChar while scanning an unterminated run of quotes without stopping at the source-buffer boundary, so peekChar reads one byte past the heap allocation. The demonstrated path requires locally supplied Wren source to reach an embedding application's compiler; the published proof of concept produces an AddressSanitizer-detected abort, while effects in uninstrumented hosts are not established.

CVSS severity3.3
Low
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Wren 0.4.0 and earlier allows local users to crash an embedding process via malformed raw string syntax. In src/vm/wren_compiler.c, readRawString repeatedly calls peekChar while scanning an unterminated run of quotes without stopping at the source-buffer boundary, so peekChar reads one byte past the heap allocation. The demonstrated path requires locally supplied Wren source to reach an embedding application's compiler; the published proof of concept produces an AddressSanitizer-detected abort, while effects in uninstrumented hosts are not established.

The record

CVE
CVE-2026-2858
Published
Feb 20, 2026
Updated
Feb 20, 2026
Vendor
wren-lang
Product
Wren
Classifications
CWE-119, CWE-125, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.1
  2. Affected versionversion=0.2
  3. Affected versionversion=0.3
  4. Affected versionversion=0.4.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

wren-lang · Wrenversion=0.1; version=0.2; version=0.3; version=0.4.0

Published CVSS scores

1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A:P
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
1.9VulDBCVSS: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
3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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