CVE-2022-37436 | Apache HTTP Server: mod_proxy prior to 2.4.55 allows a backend to trigger HTTP response splitting

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.

Published: 2023-01-17 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-37436 is rated Moderate Risk (60.8/100): CVSS Medium severity, with high exploitation likelihood (EPSS 57.94%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +57.40% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-37436

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.54% 57.94% +57.40%
2 2026-03-07 0.44% 0.54% +0.11%
3 2026-03-04 — 0.44% —

Full EPSS history (37 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-37436

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2022-37436

OS Trackers for CVE-2022-37436

vendor priority summary link
alpine — CVE-2022-37436: 1 source package rows (apache2); 7 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2022-37436
debian not yet assigned CVE-2022-37436 not yet assigned priority: Debian including 1 source packages (apache2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2022-37436
gentoo low CVE-2022-37436: 1 GLSA(s) (202309-01), 1 atom(s) (www-servers/apache); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2022-37436
redhat medium — https://access.redhat.com/security/cve/CVE-2022-37436
suse high CVE-2022-37436 severity important: SUSE including 317 source package names (2.8-13.5:apache2-utils-2.4.51-150400.6.6.1, 4.3.4.9.25.2:apache2-2.4.51-150400.6.6.1, …), 595 product×package rows across 89 product lines (Container bci/php-apache, Container suse/manager/4.3/proxy-httpd, … (89 product lines)): Fixed 364, Known Affected 231. https://www.suse.com/security/cve/CVE-2022-37436/
ubuntu medium CVE-2022-37436 medium priority: Ubuntu including 1 source packages (apache2), 13 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): released 12, needed 1. https://ubuntu.com/security/CVE-2022-37436

Affected software / configurations for CVE-2022-37436

Vendor Product Version Raw CPE
apache http_server < 2.4.55 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

References for CVE-2022-37436

cvelogic Threat Intelligence