An incorrect buffer size calculation vulnerability exists in tinyexpr commit 4a7456e in…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-131 and the CVSS impact.
Summary
An incorrect buffer size calculation vulnerability exists in tinyexpr commit 4a7456e in new_expr(). For arity-0 expression nodes, including constants, variables, and zero-argument functions, the function allocates less memory than sizeof(te_expr) but treats the returned allocation as a complete te_expr object. This results in undefined behavior and can cause deterministic process termination in UBSan-instrumented builds.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-88355
- 2026-10-03 Alias added: GHSA-8v6x-g49v-x5cf
- 2026-10-06 CVSS score added · CISA ADP
- 2026-10-06 Weakness changed · CISA ADP
- 2026-10-06 CISA SSVC decision points changed
- 2026-10-06 Priority changed: LOW → HIGH
References
Sources
- CVE-2026-88355 · CVE Program
- CVE-2026-88355 · NVD
- FIRST EPSS
- GHSA-8v6x-g49v-x5cf · GitHub Advisory Database · CC BY 4.0
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