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UK Cyber Defence
VulnerabilityAwaiting Analysis

CVE-2023-54404

Zod schema-validation library contains an uncontrolled resource consumption vulnerability that allows attackers to exhaust memory by submitting a large array, set or map to an application that uses a container schema without an explicit size constraint.

HIGH 8.2EPSS 0.35%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.35%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Zod schema-validation library contains an uncontrolled resource consumption vulnerability that allows attackers to exhaust memory by submitting a large array, set or map to an application that uses a container schema without an explicit size constraint. The handleArrayResult parse logic in $ZodArray (and the equivalent set and map paths) accumulates every validation issue for each failing element with no cap or early termination, causing the process to allocate one issue object per element and crash under out-of-memory conditions. This is reachable in the default configuration whenever a container schema such as z.array() is declared without a size bound. The upstream change in commit e06a510 (pull request 6652, first released in 4.6.6) only moves the .max(), .length() and .size() size checks to run before element parsing, so it rejects oversized input for schemas that declare an explicit upper bound; per the maintainer, unbounded containers are unchanged. No released version remediates the unbounded (default) case described here, and an opt-in setting to cap total accumulated errors was proposed but not merged.

CVSS 4.0
8.2 HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.35% probability · 28th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-770, CWE-1188
Source
disclosure@vulncheck.com
EPSS trend
0%3%5%2 October 2026: 0.34%26 October 2026: 0.35%2 October 202626 October 2026

EPSS moved from 0.3% on 2 October 2026 to 0.3% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.