How severe is CVE-2023-37475?

CVE-2023-37475 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-37475?

CVE-2023-37475 affects the following packages: github.com/hamba/avro (Go), github.com/hamba/avro/v2 (Go). Ecosystems affected: Go.

How do I fix CVE-2023-37475?

Update github.com/hamba/avro to 2.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37475 is resolved across your whole dependency graph.

How do I detect CVE-2023-37475 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/hamba/avro. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2023-37475 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2023-37475?

O3 pinpoints whether CVE-2023-37475 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2023-37475 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2023-37475, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-37475?

CVE-2023-37475 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 52th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-37475?

CVE-2023-37475 is classified as Uncontrolled Resource Consumption (CWE-400). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-37475 published, and has it been updated?

CVE-2023-37475 was published on July 17, 2023 and was last updated on April 2, 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

CVE-2023-37475

HIGH

Attacker-controlled parameter can cause denial of service in hamba avro

Also known asGHSA-9x44-9pgq-cf45GO-2023-1930

Published

Jul 17, 2023

Updated

Apr 2, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk52th percentile-0.63%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

🐹github.com/hamba/avro🐹github.com/hamba/avro/v2

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

Hamba avro is a go lang encoder/decoder implementation of the avro codec specification. In affected versions a well-crafted string passed to avro's github.com/hamba/avro/v2.Unmarshal() can throw a fatal error: runtime: out of memory which is unrecoverable and can cause denial of service of the consumer of avro. The root cause of the issue is that avro uses part of the input to Unmarshal() to determine the size when creating a new slice and hence an attacker may consume arbitrary amounts of memory which in turn may cause the application to crash. This issue has been addressed in commit b4a402f4 which has been included in release version 2.13.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/hamba/avro`	all versions	2.13.0
🐹Go	`github.com/hamba/avro/v2`	all versions	2.13.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Hamba avro is a go lang encoder/decoder implementation of the avro codec…

github.comNVDJul 2023

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/hamba/avro. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/hamba/avro to 2.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37475 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-37475 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2023-37475. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Hamba avro is a go lang encoder/decoder implementation of the avro codec specification. In affected versions a well-crafted string passed to avro's `github.com/hamba/avro/v2.Unmarshal()` can throw a `fatal error: runtime: out of memory` which is unrecoverable and can cause denial of service of the consumer of avro. The root cause of the issue is that avro uses part of the input to `Unmarshal()` to determine the size when creating a new slice and hence an attacker may consume arbitrary amounts of memory which in turn may cause the application to crash. This issue has been addressed in commit `b

O3 Security · Impact-Aware SCA

Is CVE-2023-37475 in your dependencies?

O3 detects CVE-2023-37475 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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