High [CVE-2026-86145] Out-of-bounds write allows arbitrary code execution via crafted regular expressions
This high-severity Red Hat Linux advisory covers CVE-2026-86145 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
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Summary
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.
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. Red Hat severity: Important — CVSS 8.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L).
Weakness: CWE-787. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat Hardened Images; Red Hat OpenShift Container Platform 4.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: mariadb10.11; Red Hat package: mariadb11.8; Red Hat package: mingw-pcre2; Red Hat package: pcre2.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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