Memory corruption via OID decoder bounds errors
Published Apr 9, 2026 · Updated Apr 9, 2026
Heap out-of-bounds writes in wolfSSL 5.9.0 and earlier allow remote authenticated users to corrupt memory via crafted ASN.1 OIDs. DecodeObjectId checks for only one free output slot before writing two initial arcs, while DumpOID and the unknown-extension callback pass a byte size instead of a 32-element count. Reachability requires an application path that decodes attacker-controlled OIDs; the documented two-byte or short arc-array overwrite has no published code-execution outcome.
Summary
What happened
Heap out-of-bounds writes in wolfSSL 5.9.0 and earlier allow remote authenticated users to corrupt memory via crafted ASN.1 OIDs. DecodeObjectId checks for only one free output slot before writing two initial arcs, while DumpOID and the unknown-extension callback pass a byte size instead of a 32-element count. Reachability requires an application path that decodes attacker-controlled OIDs; the documented two-byte or short arc-array overwrite has no published code-execution outcome.
The record
- CVE
- CVE-2026-5187
- Published
- Apr 9, 2026
- Updated
- Apr 9, 2026
- Vendor
- wolfSSL
- Product
- wolfSSL
- Classifications
- CWE-787, CWE-122
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 9, 2026CVE publishedPublication date reported by the CVE source.
- Apr 9, 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=0 <=5.9.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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