GHSA-8gq9-2x98-w8hf — protobuf
HIGHGHSA-8gq9-2x98-w8hf is a high-severity (CVSS 7.5) CWE-1286 vulnerability in protobuf. A fix is available for protobuf — see the affected versions and patch details below.
protobuf-cpp and protobuf-python have potential Denial of Service issue
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-8gq9-2x98-w8hf.
EPSS Exploitation Probability
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.
How urgent is this, really
GHSA-8gq9-2x98-w8hf plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
protobuf🐍protobuf🐍protobuf🐍protobufReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A message parsing and memory management vulnerability in ProtocolBuffer’s C++ and Python implementations can trigger an out of memory (OOM) failure when processing a specially crafted message, which could lead to a denial of service (DoS) on services using the libraries.
Reporter: ClusterFuzz
Affected versions: All versions of C++ Protobufs (including Python) prior to the versions listed below.
Severity & Impact
As scored by google
Medium 5.7 - CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Asscored byt NIST
High 7.5 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
A small (~500 KB) malicious payload can be constructed which causes the running service to allocate more than 3GB of RAM.
Proof of Concept
For reproduction details, please refer to the unit test that identifies the specific inputs that exercise this parsing weakness.
Mitigation / Patching
Please update to the latest available versions of the following packages:
- protobuf-cpp (3.18.3, 3.19.5, 3.20.2, 3.21.6)
- protobuf-python (3.18.3, 3.19.5, 3.20.2, 4.21.6)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | protobuf | all versions | 3.18.3pip install --upgrade 'protobuf==3.18.3' |
| 🐍PyPI | protobuf | ≥ 3.19.0&&< 3.19.5 | 3.19.5pip install --upgrade 'protobuf==3.19.5' |
| 🐍PyPI | protobuf | ≥ 3.20.0&&< 3.20.2 | 3.20.2pip install --upgrade 'protobuf==3.20.2' |
| 🐍PyPI | protobuf | ≥ 4.0.0&&< 4.21.6 | 4.21.6pip install --upgrade 'protobuf==4.21.6' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for protobuf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update protobuf to 3.18.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8gq9-2x98-w8hf 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-8gq9-2x98-w8hf can be triaged on real exposure rather than presence alone.
Tailored to GHSA-8gq9-2x98-w8hf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 9 | protobuf-0:3.14.0-16.el9 | RHSA-2025:7138 |
Frequently Asked Questions
Is GHSA-8gq9-2x98-w8hf in your dependencies?
O3 Security finds GHSA-8gq9-2x98-w8hf across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.