CVE-2020-11985

IP address spoofing when proxying using mod_remoteip and mod_rewrite For configurations using proxying with mod_remoteip and certain mod_rewrite rules, an attacker could spoof their IP address for logging and PHP scripts. Note this issue was fixed in Apache HTTP Server 2.4.24 but was retrospectively allocated a low severity CVE in 2020.

Published: 2020-08-07 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-11985 is rated Moderate Risk (54.8/100): CVSS Medium severity, with high exploitation likelihood (EPSS 6.81%, 93th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. 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-2020-11985

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 2026-07-07 5.88% 6.81% +0.92%
2 2026-06-23 6.09% 5.88% -0.21%
3 2026-06-15 — 6.09% —

Full EPSS history (59 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-11985

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]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-11985

OS Trackers for CVE-2020-11985

vendor priority summary link
debian not yet assigned CVE-2020-11985 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-2020-11985
gentoo normal CVE-2020-11985: 1 GLSA(s) (202008-04), 1 atom(s) (www-servers/apache); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-11985
redhat medium — https://access.redhat.com/security/cve/CVE-2020-11985
suse high CVE-2020-11985 severity important: SUSE including 13 source package names (apache2, apache2-2.4.23-29.63.1, …), 162 product×package rows across 32 product lines (HPE Helion OpenStack 8, SUSE Enterprise Storage 5, … (32 product lines)): Fixed 133, Known Not Affected 29. https://www.suse.com/security/cve/CVE-2020-11985/
ubuntu low CVE-2020-11985 low priority: Ubuntu including 1 source packages (apache2), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 13, released 2, needed 1. https://ubuntu.com/security/CVE-2020-11985

Affected software / configurations for CVE-2020-11985

Vendor Product Version Raw CPE
apache http_server >= 2.4.1, <= 2.4.23 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

References for CVE-2020-11985

URL Tags
https://httpd.apache.org/security/vulnerabilities_24.html Vendor Advisory
https://lists.apache.org/thread.html/r03ee478b3dda3e381fd6189366fa7af97c980d2f602846eef935277d%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r09bb998baee74a2c316446bd1a41ae7f8d7049d09d9ff991471e8775%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r3c5c3104813c1c5508b55564b66546933079250a46ce50eee90b2e36%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rcc44594d4d6579b90deccd4536b5d31f099ef563df39b094be286b9e%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rd336919f655b7ff309385e34a143e41c503e133da80414485b3abcc9%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A2RN46PRBJE7E7OPD4YZX5SVWV5QKGV5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HYVYE2ZERFXDV6RMKK3I5SDSDQLPSEIQ/
https://security.gentoo.org/glsa/202008-04 Third Party Advisory
https://security.netapp.com/advisory/ntap-20200827-0002/
https://www.oracle.com/security-alerts/cpujan2021.html
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