CVE-2026-32327: A bug in APR-util version 1.6.3 (and earlier) allows a stack recursion attack against any library consumer whi

This month

CRITICAL 9.1REMOTEWATCHLISTUPGRADE

CVE-2026-32327 is a critical-severity flaw (CVSS 9.1) affecting apr-util. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A bug in APR-util version 1.6.3 (and earlier) allows a stack recursion attack against any library consumer which parses XML from untrusted sources and uses the apr_xml_quote_elem() function. Users are recommended to upgrade to version 1.6.4, which fixes this issue.

Why this priority

Critical severity
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-674
Published	2026-08-06
Last modified	2026-10-23

Publisher (CNA): Apache Software Foundation · Vendor: apache

Am I affected?

Timeline

2026-08-06 15:16 UTCPublished CVE record published
2026-10-23 21:10 UTCUpdated Record last modified

apache apr-util UPGRADE

Affected: < 1.6.4

Fixed in: 1.6.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy apr-util || rpm -q apr-util || apr-util --version

2. UPGRADE to 1.6.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade apr-util

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade apr-util

Note

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

Exact fixes by distribution

Fedora 46 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source

sudo dnf upgrade --advisory=FEDORA-2026-95888f332b

Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source

sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273

Ubuntu 20.04 · apr-util · FIXED · 1.6.1-4ubuntu2.2+esm1

sudo apt update && sudo apt install --only-upgrade apr-util dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apr-util)" ge "1.6.1-4ubuntu2.2+esm1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · apr-util · FIXED · 1.6.1-5ubuntu4.22.04.3

sudo apt update && sudo apt install --only-upgrade apr-util dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apr-util)" ge "1.6.1-5ubuntu4.22.04.3" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · apr-util · FIXED · 1.6.3-1.1ubuntu7.1

sudo apt update && sudo apt install --only-upgrade apr-util dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apr-util)" ge "1.6.3-1.1ubuntu7.1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · apr-util · FIXED · 1.6.3-1+deb12u1

sudo apt update && sudo apt install --only-upgrade apr-util dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apr-util)" ge "1.6.3-1+deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · apr-util · FIXED · 1.6.3-3+deb13u1

sudo apt update && sudo apt install --only-upgrade apr-util dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apr-util)" ge "1.6.3-3+deb13u1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · apr-util · FIXED · apr-util-1.6.3-23.el10_2.1

sudo dnf upgrade --advisory=RHSA-2026:66392 rpm -q apr-util

RHEL 8 · apr-util · FIXED · apr-util-1.6.1-9.el8_10.1

sudo dnf upgrade --advisory=RHSA-2026:69113 rpm -q apr-util

RHEL 9 · apr-util · FIXED · apr-util-1.6.1-23.el9_8.1

sudo dnf upgrade --advisory=RHSA-2026:66341 rpm -q apr-util

RHEL 6 · apr-util · DEFERRED

RHEL 7 · apr-util · DEFERRED

Alpine 3.21 · apr-util · FIXED · apr-util-1.6.4-r0

apk add --upgrade apr-util apk info -v apr-util

Alpine 3.22 · apr-util · FIXED · apr-util-1.6.4-r0

apk add --upgrade apr-util apk info -v apr-util

Alpine 3.23 · apr-util · FIXED · apr-util-1.6.4-r0

apk add --upgrade apr-util apk info -v apr-util

Alpine 3.24 · apr-util · FIXED · apr-util-1.6.4-r0

apk add --upgrade apr-util apk info -v apr-util

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2115 · source

sudo dnf update --advisory=ALAS2023-2026-2115

Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3892 · source

sudo yum update --advisory=ALAS2-2026-3892

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-3892 (important): apr-util 2026-08-31

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.

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References

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