Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Remote unauthenticated network attacker, low complexity, no UI; pure memory-exhaustion DoS gives A:H with no confidentiality or integrity impact - matches the vendor 7.5.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
3DescriptionCVE.org
A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a single connection and withholding reads. This action causes the methodOverflowQueue to grow without limit, leading to unbounded heap memory consumption and a denial of service due to memory exhaustion.
AnalysisAI
Unbounded heap memory consumption in Netty's HttpServerCodec (io.netty:netty-codec-http) lets a remote, unauthenticated attacker drive a denial of service by exhausting server memory. An attacker who pipelines multiple HTTP/1.1 requests on a single connection and withholds reads prevents the internal methodOverflowQueue from being drained, so memory grows without limit; the assessed CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, base 7.5) is availability-only with no confidentiality or integrity impact, and no public exploit code was identified at time of analysis. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitable against any HTTP/1.1 server built on Netty's HttpServerCodec that accepts pipelined requests - the default HTTP server codec behavior. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, base 7.5) is internally consistent and credible: a remote, unauthenticated attacker over the network can trigger an availability-only impact with low attack complexity and no user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Vendor-released patch: Netty 4.1.138.Final (4.1.x line) and Netty 4.2.18.Final (4.2.x line), as documented in the release notes at https://github.com/netty/netty/releases/tag/netty-4.1.138.Final and https://github.com/netty/netty/releases/tag/netty-4.2.18.Final; upgrade to the appropriate fixed release for the branch in use and rebuild any shaded or fat-jar distributions that embed Netty. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all internet-facing and internal services using Netty's HttpServerCodec, assess exposure, and if immediate patching is not possible, enforce connection read timeouts and limit HTTP/1.1 pipelining to mitigate memory exhaustion. …
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-82902
GHSA-c593-fgx2-8jj6