Two-byte heap disclosure via uninitialized serialization padding
Published Sep 11, 2026 · Updated Sep 11, 2026
Information disclosure in PCRE2 10.45 through 10.47 allows local users to read two uninitialized heap bytes via serialized regex data. For certain Unicode character classes and compile options, pcre2_compile_class.c leaves 16-bit padding uninitialized, and pcre2_serialize_encode copies it into output. Exploitation requires an embedding application to expose serialized bytes; disclosure is limited to two hard-to-control bytes from prior allocations.
Summary
What happened
Information disclosure in PCRE2 10.45 through 10.47 allows local users to read two uninitialized heap bytes via serialized regex data. For certain Unicode character classes and compile options, pcre2_compile_class.c leaves 16-bit padding uninitialized, and pcre2_serialize_encode copies it into output. Exploitation requires an embedding application to expose serialized bytes; disclosure is limited to two hard-to-control bytes from prior allocations.
The record
- CVE
- CVE-2026-89162
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- PCRE2 Project
- Product
- PCRE2
- Classifications
- CWE-908, T1005
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 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.
- Affected versionversion=10.45 <10.48
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- pcre2_serialize_encode Valgrind proof of conceptproof of concept · demonstrated
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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