Description
In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnerable to padding oracle attacks, particularly with CBC.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.0 to 2.4.23 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | apache2 | 2.4.25-1 | — |
| Debian 13 | apache2 | 2.4.25-1 | — |
| Debian 12 | apache2 | 2.4.25-1 | — |
| Debian 8 | apache2 | 2.4.10-10+deb8u8 | DSA-3796-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | apache2 | 2.4.18-2ubuntu3.2 | USN-3279-1 |
| Ubuntu 14.04 LTS | apache2 | 2.4.7-1ubuntu4.15 | USN-3279-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | httpd +5 | 2.4.6-45.el7_3.4 | RHSA-2017:0906 |
| RHEL 7 | mod_ssl +1 | 1:2.4.6-45.el7_3.4 | RHSA-2017:0906 |
| RHEL 2 | httpd24-httpd +5 | 2.4.25-9.el6 | RHSA-2017:1161 |
| RHEL 2 | httpd24-mod_ssl +1 | 1:2.4.25-9.el6 | RHSA-2017:1161 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +7 | 2.4.23-120.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_security | 2.9.1-19.GA.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.23-120.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.0.2h-13.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | apache2 | 2.4.23-21.1 | SUSE-SU-2017:0797-1 |
| SLES 12 SP1 | apache2 | 2.4.16-19.1 | SUSE-SU-2017:0801-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP2 | apache2 | 2.4.23-21.1 | SUSE-SU-2017:0797-1 |
| SLES for SAP 12 SP1 | apache2 | 2.4.16-19.1 | SUSE-SU-2017:0801-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | httpd +5 | 2.4.6-45.0.1.el7_3.4 | ELSA-2017-0906 |
| Oracle Linux 7 | mod_ssl +1 | 1:2.4.6-45.0.1.el7_3.4 | ELSA-2017-0906 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Apache mod_session_crypto - Padding Oracle EDB-40961 · webapps · Dec 23, 2016
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 10
- RHSA-2017:1414 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.23 Service Pack 1 for RHEL 6 Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:1413 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.23 Service Pack 1 for RHEL 7 Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:1161 Red Hat Security Advisory: httpd24-httpd security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:0906 Red Hat Security Advisory: httpd security and bug fix update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-3279-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3796-1 apache2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:0801-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0797-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2025-0370 Apple Mac OS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 13, 2025
- ELSA-2017-0906 Moderate: httpd security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 12, 2017
References
- https://support.apple.com/HT208221
- DSA-3796 vendor-advisory
- 40961 exploit
- 1037508 vdb-entry
- RHSA-2017:1413 vendor-advisory
- RHSA-2017:1161 vendor-advisory
- https://www.tenable.com/security/tns-2017-04
- RHSA-2017:1414 vendor-advisory
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03725en_us
- 95078 vdb-entry
- RHSA-2017:1415 vendor-advisory
- RHSA-2017:0906 vendor-advisory
- https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2016-0736
- GLSA-201701-36 vendor-advisory
- https://security.netapp.com/advisory/ntap-20180423-0001/
- [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/vulnerabilit mailing-list
- [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/vulnerabilit mailing-list
- [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/vulnerabilit mailing-list
- [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/vulnerabilit mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [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.ht mailing-list
- [httpd-cvs] 20210330 svn commit: r1888194 [10/13] - /httpd/site/trunk/content/security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [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 mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [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/vulnerabiliti mailing-list