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CRITICAL severity

CVE-2022-42920 — bcel

CRITICAL

CVE-2022-42920 is a critical-severity (CVSS 9.8) Out-of-bounds Write vulnerability in org.apache.bcel:bcel. A fix is available for org.apache.bcel:bcel — see the affected versions and patch details below.

Apache Commons BCEL prior to 6.6.0 allows producing arbitrary bytecode via out-of-bounds writing

Also known asGHSA-97xg-phpr-rg8q
Published
Nov 7, 2022
Updated
Aug 12, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 17, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
3.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs87th percentile — riskier than 87% of all scored CVEsHighest risk

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

CVE-2022-42920 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 377,166 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

1 pkg affected
☕org.apache.bcel:bcel

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

Apache Commons BCEL has a number of APIs that would normally only allow changing specific class characteristics. However, due to an out-of-bounds writing issue, these APIs can be used to produce arbitrary bytecode. This could be abused in applications that pass attacker-controllable data to those APIs, giving the attacker more control over the resulting bytecode than otherwise expected. Update to Apache Commons BCEL 6.6.0.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.apache.bcel:bcelall versions6.6.0org.apache.bcel:bcel:6.6.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.bcel:bcel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.apache.bcel:bcel to 6.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-42920 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-42920 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2022-42920. 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.

Red HatImportant

Fuse 7 ships the code in question but does not utilize it in the product, so it is affected at a reduced impact of Moderate.

ProductFixed inAdvisory
Migration Toolkit for Runtimes 1 on RHEL 8mtr/mtr-operator-bundle:1.0-30RHSA-2023:0470
Migration Toolkit for Runtimes 1 on RHEL 8org.jboss.windup-windup-parentRHSA-2023:0471
MTA-6.0-RHEL-8mta/mta-ui-rhel8:6.0.1-10RHSA-2023:0934
Red Hat AMQ Streams 2.7.0see advisoryRHSA-2024:3527
Red Hat Enterprise Linux 7bcel-0:5.2-19.el7_9RHSA-2022:8958
Red Hat Enterprise Linux 9bcel-0:6.4.1-9.el9_1RHSA-2023:0005
Red Hat Enterprise Linux 9.0 Extended Update Supportbcel-0:6.4.1-9.el9_0RHSA-2023:0004
Red Hat Fuse 7.12apache-bcelRHSA-2023:3954
UbuntuCRITICAL
USN-7208-1Ubuntu

Frequently Asked Questions

Apache Commons BCEL has a number of APIs that would normally only allow changing specific class characteristics. However, due to an out-of-bounds writing issue, these APIs can be used to produce arbitrary bytecode. This could be abused in applications that pass attacker-controllable data to those APIs, giving the attacker more control over the resulting bytecode than otherwise expected. Update to Apache Commons BCEL 6.6.0.
O3 Security · Impact-Aware SCA

Is CVE-2022-42920 in your dependencies?

O3 Security finds CVE-2022-42920 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works
CVE-2022-42920: bcel (Critical 9.8) | O3 Security