CVE-2023-25690
CriticalExploitedPublic exploitSome mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack.
Published Dec 13, 2023 · Updated Oct 8, 2026 · Also known as ALPINE-CVE-2023-25690, BIT-apache-2023-25690, DEBIAN-CVE-2023-25690, DLA-3401-1, SUSE-SU-2023:0764-1, SUSE-SU-2023:0799-1, SUSE-SU-2023:0803-1, SUSE-SU-2023:1573-1, SUSE-SU-2023:1658-1, TR-23-0134, TR-23-0175, TR-23-0197, TR-23-0698, UBUNTU-CVE-2023-25690, USN-5942-1, USN-5942-2
Key Facts
Patch immediately- CVE-2023-25690 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting HTTP Server (Apache), apache2 (alpine), apache (bitnami) and 22 more products.
- It is exploited in the wild, listed in Industry KEV feed since Jul 25, 2024. Public exploit code is available.
- EPSS estimates a 85% probability of exploitation in the next 30 days.
- Fixed versions are available, including apache 2.4.56, HTTP Server <=2.4.55, apache2 2.4.18-2ubuntu3.17+esm10.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
85%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
1 catalog listing
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2023-25690 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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:
RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/
Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Jul 25, 2024 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
355 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| HTTP ServerApache | >= 2.4.0 | 2.4.55 |
| apache2alpine | See advisory | 2.4.56-r0 |
| apachebitnami | >= 2.4.0 | 2.4.56 |
| rootio-apache2rootio | See advisory | 2.4.56-1 |
| httpdalma | See advisory | 2.4.37-51.module_el8.7.0+3515+9e4fe0d6.5 |
Patched Releases
apache
2.4.56
HTTP Server
<=2.4.55
apache2
2.4.18-2ubuntu3.17+esm10, 2.4.23-29.97.1, 2.4.29-1ubuntu4.27, 2.4.33-150000.3.75.1, 2.4.38-3+deb10u10, 2.4.41-4ubuntu3.14, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.52-1ubuntu4.4, 2.4.56-1, 2.4.56-1.1, 2.4.56-1~deb11u1, 2.4.56-r0, 2.4.66-150400.6.57.1
apache2-devel
2.4.33-150000.3.75.1, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.66-150400.6.57.1
apache2-doc
2.4.23-29.97.1, 2.4.33-150000.3.75.1, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.66-150400.6.57.1
apache2-event
2.4.51-150400.6.11.1
apache2-example-pages
2.4.23-29.97.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1
apache2-prefork
2.4.23-29.97.1, 2.4.33-150000.3.75.1, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.66-150400.6.57.1
apache2-utils
2.4.23-29.97.1, 2.4.33-150000.3.75.1, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.66-150400.6.57.1
apache2-worker
2.4.23-29.97.1, 2.4.33-150000.3.75.1, 2.4.51-150200.3.56.1, 2.4.51-150400.6.11.1, 2.4.51-35.25.1, 2.4.66-150400.6.57.1
httpd
0:2.4.53-7.el9_1.5, 0:2.4.6-98.el7_9.7, 2.4.37-51.0.1.module+el8.7.0+21029+de29ba63.5, 2.4.37-51.module_el8.7.0+3515+9e4fe0d6.5, 2.4.37-51.module+el8.7.0+1059+126e9251, 2.4.53-7.0.1.el9_1.5, 2.4.53-7.el9_1.5, 2.4.56-1, 2.4.56-1.amzn2, 2.4.56-1.amzn2023, 2.4.56-1.ph3, 2.4.56-1.ph4, 2.4.6-98.0.3.el7_9.7
httpd-core
2.4.53-7.0.1.el9_1.5, 2.4.56-1.amzn2023
httpd-devel
2.4.37-51.0.1.module+el8.7.0+21029+de29ba63.5, 2.4.53-7.0.1.el9_1.5, 2.4.56-1.amzn2, 2.4.56-1.amzn2023, 2.4.56-1.ph4, 2.4.6-98.0.3.el7_9.7
httpd-docs
2.4.56-1.ph4
httpd-filesystem
2.4.37-51.0.1.module+el8.7.0+21029+de29ba63.5, 2.4.53-7.0.1.el9_1.5, 2.4.56-1.amzn2, 2.4.56-1.amzn2023
httpd-manual
2.4.37-51.0.1.module+el8.7.0+21029+de29ba63.5, 2.4.53-7.0.1.el9_1.5, 2.4.56-1.amzn2, 2.4.56-1.amzn2023, 2.4.6-98.0.3.el7_9.7
httpd-tools
2.4.37-51.0.1.module+el8.7.0+21029+de29ba63.5, 2.4.53-7.0.1.el9_1.5, 2.4.56-1.amzn2, 2.4.56-1.amzn2023, 2.4.56-1.ph4, 2.4.6-98.0.3.el7_9.7
httpd:2.4
8060020230328221009.ad008a3a
httpd24
2.4.56-1.100.amzn1
httpd24-devel
2.4.56-1.100.amzn1
httpd24-httpd
0:2.4.34-23.el7.6
httpd24-manual
2.4.56-1.100.amzn1
httpd24-tools
2.4.56-1.100.amzn1
jbcs-httpd24-httpd
0:2.4.51-39.el7jbcs, 0:2.4.51-39.el8jbcs
mod_http2
0:1.15.19-3.el9_1.5, 1.15.19-3.el9_1.5, 1.15.7-5.module_el8.7.0+3515+9e4fe0d6.4, 1.15.7-5.module+el8.6.0+823+f143cee1, 1.15.7-5.module+el8.7.0+21029+de29ba63.4, 2.0.29-3
Timeline
Publicly disclosed
Dec 13, 2023
Added to Industry KEV feed
Jul 25, 2024
Last updated
Oct 8, 2026
Weakness Type
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
References
- advisoryhttp://access.redhat.com/errata/RHSA-2023:3354
- advisoryhttps://access.redhat.com/articles/11258
- advisoryRHSA-2023:1547
- advisoryRHSA-2023:1593
- advisoryRHSA-2023:1596
FAQ
Common Questions.
Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack.
Affected: HTTP Server (Apache) versions >= 2.4.0; apache2 (alpine); apache (bitnami) versions >= 2.4.0, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Jul 25, 2024.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including apache 2.4.56, HTTP Server <=2.4.55, apache2 2.4.18-2ubuntu3.17+esm10.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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