Application crashes via lexer token buffer overwrite
Published Sep 24, 2026 · Updated Sep 24, 2026
Out-of-bounds write in Espruino 2v29 allows attackers to crash the application with crafted JavaScript containing an overlong token. jslGetTokenValueAsString() writes one byte beyond JsLex.token in RELEASE or NO_ASSERT builds, corrupting the adjacent tokenValue pointer. Reaching the fault requires a build without assertions to parse attacker-controlled JavaScript; the bounded reported consequence is memory corruption and application denial of service.
Summary
What happened
Out-of-bounds write in Espruino 2v29 allows attackers to crash the application with crafted JavaScript containing an overlong token. jslGetTokenValueAsString() writes one byte beyond JsLex.token in RELEASE or NO_ASSERT builds, corrupting the adjacent tokenValue pointer. Reaching the fault requires a build without assertions to parse attacker-controlled JavaScript; the bounded reported consequence is memory corruption and application denial of service.
The record
- CVE
- CVE-2026-88390
- Published
- Sep 24, 2026
- Updated
- Sep 24, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1499.004
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 24, 2026CVE publishedPublication date reported by the CVE source.
- Sep 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
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