GHSA-5w86-c3rq-vjj7
HIGHGHSA-5w86-c3rq-vjj7 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in io.netty:netty-codec-redis. O3 Security confirms whether GHSA-5w86-c3rq-vjj7 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Netty: Unbounded pre-allocation in RedisArrayAggregator from RESP array length
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-5w86-c3rq-vjj7.
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-5w86-c3rq-vjj7 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 357,322 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
io.netty:netty-codec-redis☕io.netty:netty-codec-redisReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
RedisArrayAggregator pre-allocates ArrayList with initial capacity equal to the RESP array element count declared in an array header. That count is taken from the wire before the corresponding child messages exist. A small malicious header can claim a huge initial capacity.
Details
The aggregator starts a new aggregation level when it receives an ArrayHeaderRedisMessage. For positive lengths it pushes AggregateState, whose constructor runs new ArrayList<>(length). No configurable maximum is applied in this handler, and the peer does not need to supply the array elements for the backing array allocation to occur.
In the same pipeline, RedisDecoder enforces RedisConstants.REDIS_MESSAGE_MAX_LENGTH for bulk string lengths but does not apply that cap to array header lengths. Declared array sizes can therefore be extremely large while still passing decoding, and the aggregator immediately attempts Object[] reservation.
io.netty.handler.codec.redis.RedisDecoder#decodeLength io.netty.handler.codec.redis.RedisArrayAggregator#decodeRedisArrayHeader
Impact
Availability / resource exhaustion via unbounded pre-allocation from untrusted RESP array headers.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.netty:netty-codec-redis | ≥ 4.2.0.Final&&< 4.2.15.Final | 4.2.15.Final |
| ☕Maven | io.netty:netty-codec-redis | all versions | 4.1.135.Final |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-codec-redis. 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 io.netty:netty-codec-redis to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5w86-c3rq-vjj7 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 GHSA-5w86-c3rq-vjj7 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 GHSA-5w86-c3rq-vjj7. 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.
This is an Important denial of service vulnerability in Netty's RedisArrayAggregator component. A remote, unauthenticated attacker can exploit this flaw by sending a specially crafted Redis array header, causing excessive memory pre-allocation and leading to resource exhaustion. This can disrupt services utilizing…
Frequently Asked Questions
Is GHSA-5w86-c3rq-vjj7 in your dependencies?
O3 detects GHSA-5w86-c3rq-vjj7 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.