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TI-2020-20048 Aliases CVE-2020-37287

Call stack corruption in Vyper with complex type arguments

Priority LOW 35CWE-131Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Vyper before 0.2.6 contains a call stack corruption flaw in which the compiler assumes each subtype size is 32 (CWE-131). Contracts that pass multi-dimensional arrays or structs to internal or external functions receive corrupted values and incorrect function outputs. A remote attacker without privileges can affect the integrity of contract results.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00251 16th percentileScored 2026-11-07
Fix Fixed vyper (vyperlang): 0.2.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vyperlangvyperbefore 0.2.60.2.6Patch availableCNA
  • vyper Vendorvyperlang Affected before 0.2.6 Fixed in 0.2.6 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:*:*:*——vyperlang
  • cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:*:*:* Versions — — ·vyperlang

Remediation

Vyper 0.2.6 fixes this flaw. Upgrade Vyper from any version before 0.2.6 to 0.2.6.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

  • Fix · CNA vyper (vyperlang) Fixed in 0.2.6

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-21 Threatist record created from CVE-2020-37287
  2. 2026-10-22 Priority changed: MEDIUM → LOW
  3. 2026-10-28 CISA SSVC decision points changed
  4. 2026-11-02 Affected versions changed · Red Hat
  5. 2026-11-02 CVSS score added · Red Hat

References

Advisory 1

  • TI-2024-16182 Vyper bounds check on built-in `slice()` function can be overflowed CVSS 3.1CRITICAL 9.8
  • TI-2024-14992 concat built-in can corrupt memory in vyper CVSS 3.1CRITICAL 9.8
  • TI-2024-16184 Vyper array negative index vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2022-08657 Integer bounds error in Vyper CVSS 3.1CRITICAL 9.8
  • TI-2022-11796 Multiple evaluation of contract address in call in vyper CVSS 3.1HIGH 8.2
  • TI-2026-78730 Optimizer miscompilation of msg.value | K in Vyper ternary branches CVSS 4.0HIGH 8.2
See all 52 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences