Local heap disclosure via unchecked symbolmap index
Published Jun 1, 2026 · Updated Jun 1, 2026
Out-of-bounds read in Janet 1.41.0 and earlier allows local users to disclose adjacent heap memory via a crafted marshalled fiber. The doframe function in src/core/debug.c uses an attacker-controlled symbolmap slot_index as a stack index without checking it against the function definition's slotcount. Exploitation requires local execution that unmarshals the payload and passes its fiber to debug/stack; the returned locals table exposes the out-of-range value, and an invalid address can crash the process.
Summary
What happened
Out-of-bounds read in Janet 1.41.0 and earlier allows local users to disclose adjacent heap memory via a crafted marshalled fiber. The doframe function in src/core/debug.c uses an attacker-controlled symbolmap slot_index as a stack index without checking it against the function definition's slotcount. Exploitation requires local execution that unmarshals the payload and passes its fiber to debug/stack; the returned locals table exposes the out-of-range value, and an invalid address can crash the process.
The record
- CVE
- CVE-2026-10267
- Published
- Jun 1, 2026
- Updated
- Jun 1, 2026
- Vendor
- Janet Language
- Product
- Janet
- Classifications
- CWE-119, CWE-125
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 1, 2026CVE publishedPublication date reported by the CVE source.
- Jun 1, 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=1.0
- Affected versionversion=1.1
- Affected versionversion=1.10
- Affected versionversion=1.11
- Affected versionversion=1.12
- Affected versionversion=1.13
- Affected versionversion=1.14
- Affected versionversion=1.15
- Affected versionversion=1.16
- Affected versionversion=1.17
- Affected versionversion=1.18
- Affected versionversion=1.19
- Affected versionversion=1.2
- Affected versionversion=1.20
- Affected versionversion=1.21
- Affected versionversion=1.22
- Affected versionversion=1.23
- Affected versionversion=1.24
- Affected versionversion=1.25
- Affected versionversion=1.26
- Affected versionversion=1.27
- Affected versionversion=1.28
- Affected versionversion=1.29
- Affected versionversion=1.3
- Affected versionversion=1.30
- Affected versionversion=1.31
- Affected versionversion=1.32
- Affected versionversion=1.33
- Affected versionversion=1.34
- Affected versionversion=1.35
- Affected versionversion=1.36
- Affected versionversion=1.37
- Affected versionversion=1.38
- Affected versionversion=1.39
- Affected versionversion=1.4
- Affected versionversion=1.40
- Affected versionversion=1.41.0
- Affected versionversion=1.5
- Affected versionversion=1.6
- Affected versionversion=1.7
- Affected versionversion=1.8
- Affected versionversion=1.9
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
- Janet debug/stack crafted-fiber 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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