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CVE-2017-9789
When under stress, closing many connections, the HTTP/2 handling code in Apache httpd 2.4.26 would sometimes access memory after it has…
- 7.5HighCVSS base score
- 9.5%Exploitation in 30 daysEPSS · top 4.5% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By apache
- 22 days later
· 22 days later
Published
- 7 years later
· 7 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 9.5% · top 4.5% of all CVEs (9 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
Apache Software Foundation · Apache HTTP Server
- affected 2.4.26
References
22
- [announce] 20170713 CVE-2017-9789: Apache httpd 2.4 Read after free in mod_http2 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://support.apple.com/HT208221 (opens in a new tab)x_refsource_CONFIRMx_transferred
- 99568 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03908en_us (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://security.netapp.com/advisory/ntap-20170911-0002/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://httpd.apache.org/security/vulnerabilities_24.html (opens in a new tab)x_refsource_CONFIRMx_transferred
- GLSA-201710-32 (opens in a new tab)vendor-advisoryx_refsource_GENTOOx_transferred
- 1038907 (opens in a new tab)vdb-entryx_refsource_SECTRACKx_transferred
- [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20190815 svn commit: r1048742 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073139 [11/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1888194 [11/13] - /httpd/site/trunk/content/security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073149 [11/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210330 svn commit: r1073146 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210603 svn commit: r1075360 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210606 svn commit: r1075467 [2/2] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.html (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2017-18717 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2017-9789)Record last updated .