CVE-2026-86145
Description
A flaw was found in PCRE2. An out-of-bounds write vulnerability exists in the pcre2_dfa_match function due to improper size checking when reusing cached workspace blocks. A remote attacker could exploit this by providing a specially crafted regular expression or a recursive pattern in conjunction with a small heap limit. This could lead to data corruption or potentially arbitrary code execution, compromising the integrity and availability of the system.
Statement
Important: An out-of-bounds write vulnerability in the PCRE2 library, specifically within the pcre2_dfa_match function, could allow arbitrary code execution. This flaw is exploitable in Red Hat products when processing attacker-controlled regular expressions or when a recursive pattern is used in conjunction with a small, API-set heap limit, making it dependent on specific application usage patterns.
Mitigation
To mitigate this Improper Protection of Alternate Path vulnerability, ensure that secondary execution branches—such as the reuse of cached memory workspaces—enforce the exact same size and boundary checks as the primary memory allocation paths. Limit exposure by preventing untrusted user input from directly controlling PCRE2 regular expressions, and strictly avoid utilizing recursive matching patterns when operating under a low heap limit. Apply a defense-in-depth strategy by validating all inputs comprehensively.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.2 | N/A | 8.2 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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