CVE-2026-33524 | Zserio: Integer Overflow in BitStreamReader and Unbounded Memory Allocation in Deserialization

Zserio is a framework for serializing structured data with a compact and efficient way with low overhead. Prior to 2.18.1, a crafted payload as small as 4-5 bytes can force memory allocations of up to 16 GB, crashing any process with an OOM error (Denial of Service). This vulnerability is fixed in 2.18.1.

Published: 2026-04-24 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33524 is rated Low Risk (36/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33524

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-30 0.04% 0.06% +0.02%
2 2026-04-25 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33524

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-33524

GitHub Security Advisory for CVE-2026-33524

GHSA-cwq5-8pvq-j65j · Severity: high · Ecosystem: maven — Zserio Runtime: Integer Overflow in BitStreamReader and Unbounded Memory Allocation in Deserialization

Affected software / configurations for CVE-2026-33524

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-33524

cvelogic Threat Intelligence