Heap over-read via release-disabled bytecode bounds check
Published Jun 15, 2026 · Updated Jun 15, 2026
Out-of-bounds read in Duktape 2.99.0 through 2.99.99 allows local users to read past a heap buffer via crafted bytecode. The loader in duk_api_bytecode.c guards the count_instr-derived length only with DUK_ASSERT, which release builds remove before processing instruction data. An embedding application must pass attacker-controlled serialized bytecode to duk_load_function; public testing demonstrates a four-byte over-read, while Ubuntu bounds the practical impact to denial of service.
Summary
What happened
Out-of-bounds read in Duktape 2.99.0 through 2.99.99 allows local users to read past a heap buffer via crafted bytecode. The loader in duk_api_bytecode.c guards the count_instr-derived length only with DUK_ASSERT, which release builds remove before processing instruction data. An embedding application must pass attacker-controlled serialized bytecode to duk_load_function; public testing demonstrates a four-byte over-read, while Ubuntu bounds the practical impact to denial of service.
The record
- CVE
- CVE-2026-12216
- Published
- Jun 15, 2026
- Updated
- Jun 15, 2026
- Vendor
- Sami Vaarala
- Product
- Duktape
- Classifications
- CWE-119
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 15, 2026CVE publishedPublication date reported by the CVE source.
- Jun 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.99.0
- Affected versionversion=2.99.1
- Affected versionversion=2.99.10
- Affected versionversion=2.99.11
- Affected versionversion=2.99.12
- Affected versionversion=2.99.13
- Affected versionversion=2.99.14
- Affected versionversion=2.99.15
- Affected versionversion=2.99.16
- Affected versionversion=2.99.17
- Affected versionversion=2.99.18
- Affected versionversion=2.99.19
- Affected versionversion=2.99.2
- Affected versionversion=2.99.20
- Affected versionversion=2.99.21
- Affected versionversion=2.99.22
- Affected versionversion=2.99.23
- Affected versionversion=2.99.24
- Affected versionversion=2.99.25
- Affected versionversion=2.99.26
- Affected versionversion=2.99.27
- Affected versionversion=2.99.28
- Affected versionversion=2.99.29
- Affected versionversion=2.99.3
- Affected versionversion=2.99.30
- Affected versionversion=2.99.31
- Affected versionversion=2.99.32
- Affected versionversion=2.99.33
- Affected versionversion=2.99.34
- Affected versionversion=2.99.35
- Affected versionversion=2.99.36
- Affected versionversion=2.99.37
- Affected versionversion=2.99.38
- Affected versionversion=2.99.39
- Affected versionversion=2.99.4
- Affected versionversion=2.99.40
- Affected versionversion=2.99.41
- Affected versionversion=2.99.42
- Affected versionversion=2.99.43
- Affected versionversion=2.99.44
- Affected versionversion=2.99.45
- Affected versionversion=2.99.46
- Affected versionversion=2.99.47
- Affected versionversion=2.99.48
- Affected versionversion=2.99.49
- Affected versionversion=2.99.5
- Affected versionversion=2.99.50
- Affected versionversion=2.99.51
- Affected versionversion=2.99.52
- Affected versionversion=2.99.53
- Affected versionversion=2.99.54
- Affected versionversion=2.99.55
- Affected versionversion=2.99.56
- Affected versionversion=2.99.57
- Affected versionversion=2.99.58
- Affected versionversion=2.99.59
- Affected versionversion=2.99.6
- Affected versionversion=2.99.60
- Affected versionversion=2.99.61
- Affected versionversion=2.99.62
- Affected versionversion=2.99.63
- Affected versionversion=2.99.64
- Affected versionversion=2.99.65
- Affected versionversion=2.99.66
- Affected versionversion=2.99.67
- Affected versionversion=2.99.68
- Affected versionversion=2.99.69
- Affected versionversion=2.99.7
- Affected versionversion=2.99.70
- Affected versionversion=2.99.71
- Affected versionversion=2.99.72
- Affected versionversion=2.99.73
- Affected versionversion=2.99.74
- Affected versionversion=2.99.75
- Affected versionversion=2.99.76
- Affected versionversion=2.99.77
- Affected versionversion=2.99.78
- Affected versionversion=2.99.79
- Affected versionversion=2.99.8
- Affected versionversion=2.99.80
- Affected versionversion=2.99.81
- Affected versionversion=2.99.82
- Affected versionversion=2.99.83
- Affected versionversion=2.99.84
- Affected versionversion=2.99.85
- Affected versionversion=2.99.86
- Affected versionversion=2.99.87
- Affected versionversion=2.99.88
- Affected versionversion=2.99.89
- Affected versionversion=2.99.9
- Affected versionversion=2.99.90
- Affected versionversion=2.99.91
- Affected versionversion=2.99.92
- Affected versionversion=2.99.93
- Affected versionversion=2.99.94
- Affected versionversion=2.99.95
- Affected versionversion=2.99.96
- Affected versionversion=2.99.97
- Affected versionversion=2.99.98
- Affected versionversion=2.99.99
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
- Duktape api_bytecode count_instr reproducerproof 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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