CVE-2023-25690: Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggli

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CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2023-25690 is a critical-severity flaw (CVSS 9.8) affecting http server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like:

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

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	84.5% (top 1%)
CISA exploited list	No
Weakness	CWE-444
Published	2023-03-07
Last modified	2026-06-17

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

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

Am I affected?

Timeline

2023-03-07 16:15 UTCPublished CVE record published
2026-06-17 05:41 UTCUpdated Record last modified

apache http server UPGRADE

Affected: >= 2.4.0 and <= 2.4.55

Fixed in: newer than 2.4.55

Safe to downgrade to: a release before 2.4.0

1. Check installed version

apt-cache policy http-server || rpm -q http-server || http-server --version

2. UPGRADE to newer than 2.4.55 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade http-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade http-server

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 2.4.0 (Debian / Ubuntu)

apt-cache madison http-server sudo apt install http-server=<VERSION_BEFORE_2.4.0> sudo apt-mark hold http-server

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

dnf --showduplicates list http-server sudo dnf downgrade http-server-<VERSION_BEFORE_2.4.0> sudo dnf versionlock add http-server

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.

Exact fixes by distribution

Fedora ELN · python-wrapt · FIXED · 2.5.2-1.eln159 · FEDORA-2026-5503ee9370 · source

sudo dnf upgrade --advisory=FEDORA-2026-5503ee9370

Fedora 46 · python-wrapt · FIXED · 2.5.2-1.fc46 · FEDORA-2026-8a83579801 · source

sudo dnf upgrade --advisory=FEDORA-2026-8a83579801

Ubuntu 20.04 · apache2 · FIXED · 2.4.41-4ubuntu3.14

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.41-4ubuntu3.14" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · apache2 · FIXED · 2.4.52-1ubuntu4.4

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.52-1ubuntu4.4" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · apache2 · FIXED · 2.4.55-1ubuntu2

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.55-1ubuntu2" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.10 · apache2 · FIXED · 2.4.55-1ubuntu2

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.55-1ubuntu2" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.04 · apache2 · FIXED · 2.4.55-1ubuntu2

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.55-1ubuntu2" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · apache2 · FIXED · 2.4.56-1

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.56-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · apache2 · FIXED · 2.4.56-1

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.4.56-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 7 · httpd · FIXED · httpd-2.4.6-98.el7_9.7

sudo dnf upgrade --advisory=RHSA-2023:1593 rpm -q httpd

RHEL 9 · httpd · FIXED · httpd-2.4.53-7.el9_1.5

sudo dnf upgrade --advisory=RHSA-2023:1670 rpm -q httpd

RHEL 9 · mod_http2 · FIXED · mod_http2-1.15.19-3.el9_1.5

sudo dnf upgrade --advisory=RHSA-2023:1670 rpm -q mod_http2

RHEL 9.0 Extended Update Support · httpd · FIXED · httpd-2.4.51-7.el9_0.4

sudo dnf upgrade --advisory=RHSA-2023:1916 rpm -q httpd

RHEL 9.0 Extended Update Support · mod_http2 · FIXED · mod_http2-1.15.19-3.el9_0.5

sudo dnf upgrade --advisory=RHSA-2023:1916 rpm -q mod_http2

Alpine 3.20 · apache2 · FIXED · apache2-2.4.56-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.21 · apache2 · FIXED · apache2-2.4.56-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.22 · apache2 · FIXED · apache2-2.4.56-r0

apk add --upgrade apache2 apk info -v apache2

Alpine 3.23 · apache2 · FIXED · apache2-2.4.56-r0

apk add --upgrade apache2 apk info -v apache2

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2023-136 · source

sudo dnf update --advisory=ALAS2023-2023-136

Amazon Linux 2 · see advisory · FIXED · ALAS2-2023-1989 · source

sudo yum update --advisory=ALAS2-2023-1989

Amazon Linux 1 · see advisory · FIXED · ALAS-2023-1711 · source

sudo yum update --advisory=ALAS-2023-1711

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: dhmosfunk/CVE-2023-25690-POC (288 stars)
GitHub PoC: thanhlam-attt/CVE-2023-25690 (4 stars)
GitHub PoC: oOCyginXOo/CVE-2023-25690-POC (2 stars)

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-2023-25690?

http server: upgrade to newer than 2.4.55. Exact commands for each OS are on this page.

Is CVE-2023-25690 being exploited?

CVE-2023-25690 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-2023-25690 affect?

CVE-2023-25690 affects http server. Severity is critical (CVSS 9.8). Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in whi

How urgent is CVE-2023-25690?

Priority 77/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Apache HTTP Server vulnerabilities

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References

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