ZeroHour

CVE-2026-89157

mass

Out-of-Bounds Write in PCRE2 32-Bit Builds via Attacker-Supplied Large Patterns

CVSS 3.1
5.7 medium
EPSS
Published
()
Modified
AI analysis

PCRE2 before 10.48 contains an integer-overflow flaw (CWE-190) in the pcre2_pattern_convert function that leads to an out-of-bounds write, but only on 32-bit platforms and only when an attacker can supply a sufficiently large pattern. An application or service that compiles untrusted patterns on a 32-bit build is therefore exposed: successful corruption can modify memory outside the intended buffer, with the CVSS vector indicating high integrity impact and low availability impact but no confidentiality impact. Affected users are any products or deployments that ship or link a 32-bit build of PCRE2 older than 10.48 and pass attacker-controlled pattern data to the library; 64-bit deployments are not affected by this issue. No public proof-of-concept is known, the flaw is not in CISA's KEV catalog, and there are no confirmed reports of exploitation in the wild.

What to do: Upgrade PCRE2 to version 10.48 or later, and rebuild or redeploy any application that statically or dynamically bundles an older 32-bit PCRE2 (check dependencies such as PHP, Exim, PostgreSQL or other software that embeds PCRE2 rather than relying on the system copy). Until patched, restrict or reject large attacker-supplied patterns on 32-bit builds to prevent the overflow condition. 64-bit deployments do not need immediate action for this flaw.

Affected
PCRE2 project PCRE2all versions before 10.48 on 32-bit platforms
Estimated exposure
masstens of millions or more of 32-bit PCRE2 builds (library is ubiquitous; 32-bit builds persist in embedded/IoT and legacy software) — PCRE2 is one of the most widely bundled regex engines (shipped inside PHP, Exim, PostgreSQL and countless applications and operating systems), so even the subset running 32-bit builds plausibly reaches tens of millions of installations;…

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description

PCRE2 before 10.48, on 32-bit platforms, has a pcre2_pattern_convert out-of-bounds write when an attacker can provide a large pattern.

Weakness
CWE-190
Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

In the news

Re: pcre2 version 10.48 released with security fixes

PCRE2 10.48 released with security fixes; seven vulnerabilities assigned CVEs including CVE-2026-86145 and CVE-2026-89156 through CVE-2026-89162.

The PCRE2 regular expression library released version 10.48 with multiple security fixes, disclosed on the oss-security mailing list. Seven issues received CVE assignments: CVE-2026-86145, CVE-2026-89156, CVE-2026-89157, CVE-2026-89158, CVE-2026-89160, CVE-2026-89161, and CVE-2026-89162. PCRE2 is a widely used regex engine embedded in many open-source projects and applications. No exploitation is reported in the disclosure.