How severe is CVE-2026-54251?

No CVSS score has been assigned to CVE-2026-54251 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-54251?

CVE-2026-54251 affects the following packages: io.netty.incubator:netty-incubator-codec-ohttp (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-54251?

Update io.netty.incubator:netty-incubator-codec-ohttp to 0.0.23.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54251 is resolved across your whole dependency graph.

How do I detect CVE-2026-54251 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty.incubator:netty-incubator-codec-ohttp. 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-2026-54251 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-2026-54251?

O3 pinpoints whether CVE-2026-54251 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-2026-54251 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54251 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 CVE-2026-54251 published, and has it been updated?

CVE-2026-54251 was published on August 20, 2026 and was last updated on August 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-54251

CVE-2026-54251 is a security vulnerability in io.netty.incubator:netty-incubator-codec-ohttp. O3 Security confirms whether CVE-2026-54251 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

netty-incubator-codec-ohttp: [OHttpServerCodec] Native Direct-Memory Leak on AEAD Decryption Failure Leads to Gateway Denial of Service

Published

Aug 20, 2026

Updated

Aug 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 20, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

☕io.netty.incubator:netty-incubator-codec-ohttp

Real-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

The netty-incubator-codec-ohttp library implements Oblivious HTTP (OHTTP) gateway and client functionality using Netty's ByteBuf memory management. When an OHTTP gateway processes encrypted client requests, it allocates a pooled direct (native off-heap) ByteBuf to hold the decrypted plaintext before the AEAD tag is verified. If the AEAD tag check fails — meaning the ciphertext is invalid — the decryption method throws a CryptoException, but the allocated buffer is never released because no try/finally block guards the allocation.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.netty.incubator:netty-incubator-codec-ohttp`	all versions	0.0.23.Final

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty.incubator:netty-incubator-codec-ohttp. 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.incubator:netty-incubator-codec-ohttp to 0.0.23.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54251 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-2026-54251 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-2026-54251. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

The **netty-incubator-codec-ohttp** library implements Oblivious HTTP (OHTTP) gateway and client functionality using Netty's `ByteBuf` memory management. When an OHTTP gateway processes encrypted client requests, it allocates a pooled direct (native off-heap) `ByteBuf` to hold the decrypted plaintext before the AEAD tag is verified. If the AEAD tag check fails — meaning the ciphertext is invalid — the decryption method throws a `CryptoException`, but the allocated buffer is never released because no `try/finally` block guards the allocation.

O3 Security · Impact-Aware SCA

Is CVE-2026-54251 in your dependencies?

O3 detects CVE-2026-54251 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works