CVE Intelligence
Low Memory corruption

CVE-2026-114115 — Vyper 0.3.8 through 0.5.0b1 Memory Misread via Ternary Nested Array Selection

Vyper 0.3.8 through 0.5.0b1 contains a compiler miscompilation vulnerability in parse_IfExp that reads nested arrays with narrower inner bounds using the wider result type's memory layout. When a ternary selects the narrower array, inner arrays after the first are read at wrong offsets, causing contracts to silently store corrupted values or revert.

Published Oct 20, 2026 · Updated Oct 22, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: VulnCheck

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.28%
ahead of 20% of scored CVEs · Oct 26, 2026
Affects
Vyperlang
Vyper
CVSS base
3.7
Low · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Vyperlang Vyper).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Vyperlang Vyper ≥ 0.3.8 and ≤ 0.5.0b1 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.3 CVSS 4.0 Medium — — disclosure@vulncheck.com via NIST National Vulnerability Database
6.3 CVSS 4.0 Medium — — VulnCheck via CVE Program (cve.org) e CISA ADP
3.7 CVSS 3.1 Low 2.2 1.4 disclosure@vulncheck.com via NIST National Vulnerability Database
3.7 CVSS 3.1 Low — — GitHub, Inc. via GitHub Security Advisories
3.7 CVSS 3.1 Low — — VulnCheck via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-843 · Type Confusion

Other CVEs with this weakness →

EPSS over time FIRST

Oct 21, 2026 → Oct 26, 2026 · 6 reading(s) · max 0.28%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Awaiting Analysis
    Oct 22, 2026 · NIST National Vulnerability Database
  • SSVC assessment updated
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Affected products added · vyperlang/vyper
    Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 20, 2026
  • CVSS changed · 3.7
    Oct 20, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 20, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 20, 2026 · Alertas do Telegram
  • CVE published
    Oct 20, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 20, 2026 – Oct 22, 2026
  • 1× Official description updated · Oct 20, 2026 – Oct 20, 2026

References

5 on the record

Elsewhere on this site

Vyperlang
every CVE for this vendor
Memory corruption
same class
CWE-843
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-114663 Vyper 0.4.0b1 through 0.5.0b1 Name Shadowing of Imported Constants and Default Arguments 5d
  • CVE-2026-114117 Vyper 0.3.8 through 0.5.0b1 Optimizer Miscompilation of msg.value | K in Ternary Branches 6d
  • CVE-2026-114118 Vyper 0.3.4 through 0.5.0b1 create_from_blueprint Offset Validation Bypass via Unsigned Wraparound 6d
  • CVE-2026-114114 Vyper through 0.5.0b1 Literal Value Substitution via Multi-byte Characters 6d
  • CVE-2026-114116 Vyper through 0.5.0b1 Literal Value Manipulation via Line Separators 6d
  • CVE-2021-48019 Vyper before 0.2.9 Incorrect RETURNDATASIZE in create_forwarder_to Proxies 6d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-114115 is "Vyper 0.3.8 through 0.5.0b1 Memory Misread via Ternary Nested Array Selection", rated Low. It affects Vyper (Vyperlang); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.7 describes technical severity. EPSS 0.28% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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