CVE-2025-6566: A vulnerability was found in oatpp Oat++ up to 1.3.1

Q: How do I fix CVE-2025-6566?

oat\+\+: upgrade to newer than 1.3.1. Exact commands for each OS are on this page.

Q: Is CVE-2025-6566 being exploited?

CVE-2025-6566 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-6566 affect?

CVE-2025-6566 affects oat\+\+. Severity is medium (CVSS 5.3). A vulnerability was found in oatpp Oat++ up to 1.3.1. It has been declared as critical. This vulnerability affects the function deserializeArray of the file src/oatpp/json/Deserializer.cpp. The manipulation leads to stack-based buffer overf

Q: How urgent is CVE-2025-6566?

Priority 43/100. Public exploit reference; Remotely exploitable, no login, no user action

This week

MEDIUM 5.3REMOTEUPGRADE

CVE-2025-6566 is a medium-severity flaw (CVSS 5.3) affecting oat\+\+. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability was found in oatpp Oat++ up to 1.3.1. It has been declared as critical. This vulnerability affects the function deserializeArray of the file src/oatpp/json/Deserializer.cpp. The manipulation leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 44%)
CISA exploited list	No
Weakness	CWE-119, CWE-121, CWE-787
Published	2025-06-24
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: oatpp

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

Am I affected?

Timeline

2025-06-24 13:15 UTCPublished CVE record published
2026-06-17 10:02 UTCUpdated Record last modified

oatpp oat\+\+ UPGRADE

Affected: <= 1.3.1

Fixed in: newer than 1.3.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy oat++ || rpm -q oat++ || oat++ --version

2. UPGRADE to newer than 1.3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade oat++

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade oat++

Note

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

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-2025-6566?

oat\+\+: upgrade to newer than 1.3.1. Exact commands for each OS are on this page.

Is CVE-2025-6566 being exploited?

CVE-2025-6566 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-2025-6566 affect?

CVE-2025-6566 affects oat\+\+. Severity is medium (CVSS 5.3). A vulnerability was found in oatpp Oat++ up to 1.3.1. It has been declared as critical. This vulnerability affects the function deserializeArray of the file src/oatpp/json/Deserializer.cpp. The manipulation leads to stack-based buffer overf

How urgent is CVE-2025-6566?

Priority 43/100. Public exploit reference; Remotely exploitable, no login, no user action

References

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