CVE-2017-9789: apache software foundation apache http server Use After Free
Vulnerability summary
CVE-2017-9789 is a high (CVSS 7.5) Use After Free vulnerability in apache software foundation apache http server. EPSS estimates a 9.58% chance of exploitation in the next 30 days, higher than 95.4% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 10% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 2 · Related 1Timeline
- 13-07-2017PublishedVulnerability first disclosed.
- 16-09-2024Last modifiedVulnerability information updated.
Description
When under stress, closing many connections, the HTTP/2 handling code in Apache httpd 2.4.26 would sometimes access memory after it has been freed, resulting in potentially erratic behaviour.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
9.58%
Chance of exploitation in the next 30 days
Percentile
95%
Versus all other CVEs
30-day change
No change 0.00 pp
From 9.58% 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.
Alpine1 product
- apache2< 2.4.27-r0
Apache1 product
- http_server2.4.26
Apache software foundation1 product
- apache http server2.4.26
3 vendors · 3 products
References
23 links- support.apple.com/HT208221X Refsource CONFIRM
- security.netapp.com/advisory/ntap-20170911-0002/X Refsource CONFIRM