CVE-2023-52389: UTF32Encoding.cpp in POCO has a Poco::UTF32Encoding integer overflow and resultant stack buffer overflow becau

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CRITICAL 9.8REMOTEUPGRADE

CVE-2023-52389 is a critical-severity flaw (CVSS 9.8) affecting poco. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

UTF32Encoding.cpp in POCO has a Poco::UTF32Encoding integer overflow and resultant stack buffer overflow because Poco::UTF32Encoding::convert() and Poco::UTF32::queryConvert() may return a negative integer if a UTF-32 byte sequence evaluates to a value of 0x80000000 or higher. This is fixed in 1.11.8p2, 1.12.5p2, and 1.13.0.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 42%)
CISA exploited list	No
Weakness	CWE-190
Published	2024-01-27
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: pocoproject

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

Am I affected?

Timeline

2024-01-27 03:15 UTCPublished CVE record published
2026-06-17 06:42 UTCUpdated Record last modified

pocoproject poco UPGRADE

Affected: < 1.11.8 · >= 1.12.0 and < 1.12.5 · 1.11.8 · 1.11.8 p1 · 1.12.5

Fixed in: 1.11.8, 1.12.5

Safe to downgrade to: a release before 1.11.8

1. Check installed version

apt-cache policy poco || rpm -q poco || poco --version

2. UPGRADE to 1.11.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade poco

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade poco

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 1.11.8 (Debian / Ubuntu)

apt-cache madison poco sudo apt install poco=<VERSION_BEFORE_1.11.8> sudo apt-mark hold poco

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

dnf --showduplicates list poco sudo dnf downgrade poco-<VERSION_BEFORE_1.11.8> sudo dnf versionlock add poco

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-2023-52389?

poco: upgrade to 1.11.8, 1.12.5. Exact commands for each OS are on this page.

Is CVE-2023-52389 being exploited?

CVE-2023-52389 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-2023-52389 affect?

CVE-2023-52389 affects poco. Severity is critical (CVSS 9.8). UTF32Encoding.cpp in POCO has a Poco::UTF32Encoding integer overflow and resultant stack buffer overflow because Poco::UTF32Encoding::convert() and Poco::UTF32::queryConvert() may return a negative integer if a UTF-32 byte sequence evaluate

How urgent is CVE-2023-52389?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-6375 LOW 3.3 UPGRADE A vulnerability was found in poco up to 1.14.1
CVE-2025-45766 HIGH 7.0 DOWNGRADE poco v1.14.1-release was discovered to contain weak encryption

References

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