CVE-2020-13950: mod_proxy_http NULL pointer dereference
Vulnerability summary
CVE-2020-13950 is a high (CVSS 7.5) NULL Pointer Dereference vulnerability in apache software foundation apache http server. EPSS estimates a 49.37% chance of exploitation in the next 30 days, higher than 98.8% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 49% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 6 · Related 4Timeline
- 10-06-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
Apache HTTP Server versions 2.4.41 to 2.4.46 mod_proxy_http can be made to crash (NULL pointer dereference) with specially crafted requests using both Content-Length and Transfer-Encoding headers, leading to a Denial of Service
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · Red hatEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
49.37%
Chance of exploitation in the next 30 days
Percentile
99%
Versus all other CVEs
30-day change
No change 0.00 pp
From 49.37% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Redhat22 products
- httpd< 0:2.4.37-47.module+el8.6.0+15654+427eba2e.2
- httpd-debuginfo< 0:2.4.37-47.module+el8.6.0+15654+427eba2e.2
- httpd-debugsource< 0:2.4.37-47.module+el8.6.0+15654+427eba2e.2
- httpd-devel< 0:2.4.37-47.module+el8.6.0+15654+427eba2e.2
- httpd-filesystem< 0:2.4.37-47.module+el8.6.0+15654+427eba2e.2
Oracle3 products
- enterprise_manager_ops_center12.4.0.0
- instantis_enterprisetrack17.1 | 17.2 | 17.3
- zfs_storage_appliance_kit8.8
Debian2 products
- apache2< 2.4.46-6
- debian_linuxEOL9.0 | 10.0
Alpine1 product
- apache2< 2.4.48-r0
Apache1 product
- http_server≥ 2.4.41, ≤ 2.4.46
Apache software foundation1 product
- apache http server2.4.46 | 2.4.43 | 2.4.41
Fedoraproject1 product
- fedoraEOL34 | 35
Ubuntu1 product
- apache2< 2.4.41-4ubuntu3.3
8 vendors · 32 products
References
24 links- www.openwall.com/lists/oss-security/2021/06/10/4Mailing ListX Refsource MLISTREPORTThird Party Advisory
