CVE-2026-67550
Description
A flaw was found in re2, a component that provides Node.js bindings for Google's RE2 regular expression engine. An attacker can exploit a vulnerability by manipulating the lastIndex parameter with a non-ASCII input. This manipulation can lead to an out-of-bounds heap read, causing the process to crash, which results in a Denial of Service (DoS). There is also a possibility of limited information disclosure from the heap.
Statement
This flaw primarily impacts Availability with low Confidentiality impact and zero effect on Integrity (C:L, I:N, A:H). Exploitation requires an attacker to manipulate the lastIndex property prior to executing regular expression operations on non-ASCII input, causing a mismatch between UTF-8 byte validation and UTF-16 code-unit offsets. Practically, this leads to an uncatchable process crash (Denial of Service) via an out-of-bounds heap read, though minor heap memory exposure is theoretically possible. High Attack Complexity (AC:H) is assessed because the targeted Node.js application must explicitly maintain and expose stateful regex objects with attacker-controlled lastIndex properties across non-ASCII strings. Applications using stateless regex execution or not accepting external input into lastIndex are unaffected.
Mitigation
Applications using the `re2` Node.js bindings should ensure that the `lastIndex` property of regular expression objects is not directly influenced by untrusted external input. As an operational control, developers should either avoid assigning `lastIndex` from untrusted input or clamp its value to the subject's string length (`str.length`) before performing regex operations on non-ASCII subjects.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.7 | N/A | 5.7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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