CVE-2026-33524: Zserio is a framework for serializing structured data with a compact and efficient way with low overhead

Q: How do I fix CVE-2026-33524?

zserio: upgrade to 2.18.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-33524 being exploited?

CVE-2026-33524 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-33524 affect?

CVE-2026-33524 affects zserio. Severity is high (CVSS 7.5). 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

Q: How urgent is CVE-2026-33524?

Priority 42/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-33524 is a high-severity flaw (CVSS 7.5) affecting zserio. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-789
Published	2026-04-24
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: nds-association

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-24 19:17 UTCPublished CVE record published
2026-10-26 00:10 UTCUpdated Record last modified

nds-association zserio UPGRADE

Affected: < 2.18.1

Fixed in: 2.18.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy zserio || rpm -q zserio || zserio --version

2. UPGRADE to 2.18.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zserio

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zserio

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33524?

zserio: upgrade to 2.18.1. Exact commands for each OS are on this page.

Is CVE-2026-33524 being exploited?

CVE-2026-33524 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33524 affect?

CVE-2026-33524 affects zserio. Severity is high (CVSS 7.5). 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

How urgent is CVE-2026-33524?

Priority 42/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-33666 HIGH 7.5 UPGRADE Zserio is a framework for serializing structured data with a compact and efficient way with low overhead

References

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