How severe is GHSA-xhj4-g6w8-2xjw?

GHSA-xhj4-g6w8-2xjw has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-xhj4-g6w8-2xjw?

GHSA-xhj4-g6w8-2xjw affects the following packages: github.com/woven-planet/go-zserio (Go). Ecosystems affected: Go.

How do I fix GHSA-xhj4-g6w8-2xjw?

Update github.com/woven-planet/go-zserio to 0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xhj4-g6w8-2xjw is resolved across your whole dependency graph.

How do I detect GHSA-xhj4-g6w8-2xjw in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/woven-planet/go-zserio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-xhj4-g6w8-2xjw if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is GHSA-xhj4-g6w8-2xjw actively exploited in the wild?

No public exploit code has been indexed for GHSA-xhj4-g6w8-2xjw yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-xhj4-g6w8-2xjw published, and has it been updated?

GHSA-xhj4-g6w8-2xjw was published on April 24, 2026 and was last updated on June 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

CRITICAL severity

go-zserio has Unbounded Memory Allocation for All PlatformsGHSA-xhj4-g6w8-2xjw

CRITICALFix: woven-by-toyota/go-zserio@39ef1de

GHSA-xhj4-g6w8-2xjw is a critical-severity (CVSS 9.8) remote code execution vulnerability in github.com/woven-planet/go-zserio. A fix is available for github.com/woven-planet/go-zserio — see the affected versions and patch details below.

Also known asGO-2026-5759

Published

Apr 24, 2026

Updated

Jun 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Jun 25, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐹github.com/woven-planet/go-zserio

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

When deserializing arrays, strings or bytes (blob) types zserio first reads the size of the variable, and then allocates sufficient memory to load data. Since the size is always trusted this can be abused by creating a data file with a large size value, causing the zserio runtime to allocate large amounts of memory.

Patches

Please apply this commit.

Workarounds

Do not accept zserio data from non-trusted sources.
Use secure transportation protocols (like TLS).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/woven-planet/go-zserio`	all versions	0.9.1`go get github.com/woven-planet/go-zserio@v0.9.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/woven-planet/go-zserio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/woven-planet/go-zserio to 0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xhj4-g6w8-2xjw is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

### Impact When deserializing arrays, strings or bytes (blob) types zserio first reads the size of the variable, and then allocates sufficient memory to load data. Since the size is always trusted this can be abused by creating a data file with a large size value, causing the zserio runtime to allocate large amounts of memory. ### Patches Please apply [this commit](https://github.com/woven-by-toyota/go-zserio/commit/39ef1decde7e9766207794d396018776b33c6e45). ### Workarounds - Do not accept zserio data from non-trusted sources. - Use secure transportation protocols (like TLS).

O3 Security · Impact-Aware SCA

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