CVE-2020-28923: An issue was discovered in Play Framework 2.8.0 through 2.8.4

Routine

LOW 2.7UPGRADE

CVE-2020-28923 is a low-severity flaw (CVSS 2.7) affecting play framework. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Play Framework 2.8.0 through 2.8.4. Carefully crafted JSON payloads sent as a form field lead to Data Amplification. This affects users migrating from a Play version prior to 2.8.0 that used the Play Java API to serialize classes with protected or private fields to JSON.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	2.7 (Low)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Published	2020-12-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: lightbend

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-12-03 17:15 UTCPublished CVE record published
2026-06-17 03:10 UTCUpdated Record last modified

lightbend play framework UPGRADE

Affected: >= 2.8.0 and <= 2.8.4

Fixed in: newer than 2.8.4

Safe to downgrade to: a release before 2.8.0

1. Check installed version

apt-cache policy play-framework || rpm -q play-framework || play-framework --version

2. UPGRADE to newer than 2.8.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade play-framework

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade play-framework

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.8.0 (Debian / Ubuntu)

apt-cache madison play-framework sudo apt install play-framework=<VERSION_BEFORE_2.8.0> sudo apt-mark hold play-framework

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list play-framework sudo dnf downgrade play-framework-<VERSION_BEFORE_2.8.0> sudo dnf versionlock add play-framework

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-28923?

play framework: upgrade to newer than 2.8.4. Exact commands for each OS are on this page.

Is CVE-2020-28923 being exploited?

CVE-2020-28923 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-28923 affect?

CVE-2020-28923 affects play framework. Severity is low (CVSS 2.7). An issue was discovered in Play Framework 2.8.0 through 2.8.4. Carefully crafted JSON payloads sent as a form field lead to Data Amplification. This affects users migrating from a Play version prior to 2.8.0 that used the Play Java API to s

How urgent is CVE-2020-28923?

Priority 25/100. No elevated risk signals yet.

Software pages

Java vulnerabilities

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References

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