CVE-2022-37436
MediumPrior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body.
Published Mar 13, 2023 · Updated Sep 23, 2026 · Also known as ALPINE-CVE-2022-37436, BIT-apache-2022-37436, DEBIAN-CVE-2022-37436, UBUNTU-CVE-2022-37436, USN-5839-2
Key Facts
Patch immediately- CVE-2022-37436 is a medium-severity vulnerability (CVSS 5.3 v3.1) affecting HTTP Server (Apache), apache (arch), apache2 (alpine) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 56% probability of exploitation in the next 30 days.
- Fixed versions are available, including apache 2.4.55, apache 2.4.55-1, HTTP Server 2.4.55.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS (30-day exploit likelihood)
56%
Higher than 99.0% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
Get the full CVE-2022-37436 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.
Affected Products
349 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| HTTP ServerApache | See advisory | 2.4.55 |
| apachearch | See advisory | 2.4.55-1 |
| apache2alpine | See advisory | 2.4.55-r0 |
| rootio-apache2rootio | See advisory | 2.4.55-1 |
| httpdalma | See advisory | 2.4.37-51.module_el8.7.0+3405+9516b832.1 |
Patched Releases
apache
2.4.55, 2.4.55-1
HTTP Server
2.4.55
apache2
2.4.18-2ubuntu3.17+esm9, 2.4.23-29.94.1, 2.4.29-1ubuntu4.26, 2.4.33-150000.3.72.1, 2.4.38-3+deb10u9, 2.4.41-4ubuntu3.13, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.52-1ubuntu4.3, 2.4.55-1, 2.4.55-1.1, 2.4.55-r0, 2.4.56-1~deb11u1, 2.4.66-150400.6.57.1
apache2-devel
2.4.33-150000.3.72.1, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.66-150400.6.57.1
apache2-doc
2.4.23-29.94.1, 2.4.33-150000.3.72.1, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.66-150400.6.57.1
apache2-event
2.4.51-150400.6.6.1
apache2-example-pages
2.4.23-29.94.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1
apache2-prefork
2.4.23-29.94.1, 2.4.33-150000.3.72.1, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.66-150400.6.57.1
apache2-utils
2.4.23-29.94.1, 2.4.33-150000.3.72.1, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.66-150400.6.57.1
apache2-worker
2.4.23-29.94.1, 2.4.33-150000.3.72.1, 2.4.51-150200.3.51.1, 2.4.51-150400.6.6.1, 2.4.51-35.22.1, 2.4.66-150400.6.57.1
httpd
0:2.4.53-7.el9_1.1, 2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.37-51.module_el8.7.0+3405+9516b832.1, 2.4.37-51.module+el8.7.0+1059+126e9251, 2.4.53-7.0.1.el9_1.1, 2.4.53-7.el9_1.1, 2.4.55-1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023, 2.4.55-1.ph3, 2.4.55-1.ph4
httpd-core
2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2023
httpd-devel
2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023, 2.4.55-1.ph4
httpd-docs
2.4.55-1.ph4
httpd-filesystem
2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023
httpd-manual
2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023
httpd-tools
2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023, 2.4.55-1.ph4
httpd:2.4
8070020230131172653.bd1311ed
httpd24
2.4.56-1.100.amzn1
httpd24-devel
2.4.56-1.100.amzn1
httpd24-manual
2.4.56-1.100.amzn1
httpd24-tools
2.4.56-1.100.amzn1
jbcs-httpd24-httpd
0:2.4.57-5.el7jbcs, 0:2.4.57-5.el8jbcs
mod_http2
1.15.7-5.module_el8.6.0+2872+fe0ff7aa, 1.15.7-5.module+el8.6.0+20548+01710940, 1.15.7-5.module+el8.6.0+823+f143cee1, 2.0.29-3
mod_ldap
2.4.37-51.0.1.module+el8.7.0+20923+af3b70dd.1, 2.4.53-7.0.1.el9_1.1, 2.4.55-1.amzn2, 2.4.55-1.amzn2023
Timeline
Publicly disclosed
Mar 13, 2023
Last updated
Sep 23, 2026
Weakness Type
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
- CWE-436 Interpretation Conflict
References
- advisoryRHSA-2023:0852
- advisoryRHSA-2023:0970
- advisoryRHSA-2023:4628
- advisoryRHSA-2023:4629
- advisoryhttps://bugzilla.suse.com/1207247
FAQ
Common Questions.
Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body.
Affected: HTTP Server (Apache); apache (arch); apache2 (alpine), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including apache 2.4.55, apache 2.4.55-1, HTTP Server 2.4.55.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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