Description
In Apache httpd 2.0.23 to 2.0.65, 2.2.0 to 2.2.34, and 2.4.0 to 2.4.29, mod_authnz_ldap, if configured with AuthLDAPCharsetConfig, uses the Accept-Language header value to lookup the right charset encoding when verifying the user's credentials. If the header value is not present in the charset conversion table, a fallback mechanism is used to truncate it to a two characters value to allow a quick retry (for example, 'en-US' is truncated to 'en'). A header value of less than two characters forces an out of bound write of one NUL byte to a memory location that is not part of the string. In the worst case, quite unlikely, the process would crash which could be used as a Denial of Service attack. In the more likely case, this memory is already reserved for future use and the issue has no effect at all.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.0.23 to 2.0.65, 2.2.0 to 2.2.34, 2.4.0 to 2.4.29 | — |
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 | 2.4.33-1 | — |
| Debian 13 | apache2 | 2.4.33-1 | — |
| Debian 12 | apache2 | 2.4.33-1 | — |
| Debian 9 | apache2 | 2.4.25-3+deb9u4 | DSA-4164-1 |
| Debian 8 | apache2 | 2.4.10-10+deb8u12 | DSA-4164-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 7 | apache2 | 2.2.22-13+deb7u13 | DLA-1389-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | apache2 | 2.4.29-1ubuntu4.1 | USN-3627-2 |
| Ubuntu 16.04 LTS | apache2 | 2.4.18-2ubuntu3.8 | USN-3627-1 |
| Ubuntu 14.04 LTS | apache2 | 2.4.7-1ubuntu4.20 | USN-3627-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | httpd +5 | 2.4.6-93.el7 | RHSA-2020:1121 |
| RHEL 7 | mod_ssl +1 | 1:2.4.6-93.el7 | RHSA-2020:1121 |
| RHEL 3 | httpd24-curl +2 | 7.61.1-1.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-httpd +5 | 2.4.34-7.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-mod_md | 2.4.34-7.el7 | RHSA-2018:3558 |
| RHEL 3 | httpd24-mod_ssl +1 | 1:2.4.34-7.el6 | RHSA-2018:3558 |
| RHEL 3 | httpd24-nghttp2 +2 | 1.7.1-7.el6 | RHSA-2018:3558 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services 1 | jbcs-httpd24 +1 | 1-6.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apache-commons-daemon-jsvc | 1:1.1.0-3.redhat_2.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr +1 | 1.6.3-31.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr-util +8 | 1.6.1-24.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.29-35.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.8-3.Final_redhat_2.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_jk +2 | 1.2.46-1.redhat_1.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.29-35.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.29.0-9.jbcs.el6 | RHSA-2019:0367 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.0.2n-14.jbcs.el6 | RHSA-2019:0367 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | apache2 | 2.4.23-29.18.2 | SUSE-SU-2018:1161-1 |
| SLES 12 SP2 | apache2 | 2.4.23-29.18.2 | SUSE-SU-2018:1161-2, SUSE-SU-2018:1161-1 |
| SLES 12 SP1 | apache2 | 2.4.16-20.16.1 | SUSE-SU-2018:0879-1 |
| SLES 12 | apache2 | 2.4.10-14.31.1 | SUSE-SU-2018:0901-1 |
| SLES 11 SP4 | apache2 | 2.2.34-70.15.1 | SUSE-SU-2018:1079-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Studio Onsite 1.3 | apache2 | 2.2.34-70.15.1 | SUSE-SU-2018:1079-1 |
| SLES for SAP 12 SP3 | apache2 | 2.4.23-29.18.2 | SUSE-SU-2018:1161-1 |
| SLES for SAP 12 SP2 | apache2 | 2.4.23-29.18.2 | SUSE-SU-2018:1161-1 |
| SLES for SAP 12 SP1 | apache2 | 2.4.16-20.16.1 | SUSE-SU-2018:0879-1 |
| SLES for SAP 11 SP4 | apache2 | 2.2.34-70.15.1 | SUSE-SU-2018:1079-1 |
| SUSE OpenStack Cloud 7 | apache2 | 2.4.23-29.18.2 | SUSE-SU-2018:1161-1 |
| SUSE OpenStack Cloud 6 | apache2 | 2.4.16-20.16.1 | SUSE-SU-2018:0879-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | apache2 | 2.4.33-r0 | — |
| Alpine v3.23 | apache2 | 2.4.33-r0 | — |
| Alpine v3.22 | apache2 | 2.4.33-r0 | — |
| Alpine v3.21 | apache2 | 2.4.33-r0 | — |
| Alpine v3.20 | apache2 | 2.4.33-r0 | — |
Show 16 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | apache2 | 2.4.33-r0 | — |
| Alpine v3.18 | apache2 | 2.4.33-r0 | — |
| Alpine v3.17 | apache2 | 2.4.33-r0 | — |
| Alpine v3.16 | apache2 | 2.4.33-r0 | — |
| Alpine v3.15 | apache2 | 2.4.33-r0 | — |
| Alpine v3.14 | apache2 | 2.4.33-r0 | — |
| Alpine v3.13 | apache2 | 2.4.33-r0 | — |
| Alpine v3.12 | apache2 | 2.4.33-r0 | — |
| Alpine v3.11 | apache2 | 2.4.33-r0 | — |
| Alpine v3.10 | apache2 | 2.4.33-r0 | — |
| Alpine v3.9 | apache2 | 2.4.33-r0 | — |
| Alpine v3.8 | apache2 | 2.4.33-r0 | — |
| Alpine v3.7 | apache2 | 2.4.33-r0 | — |
| Alpine v3.6 | apache2 | 2.4.33-r0 | — |
| Alpine v3.5 | apache2 | 2.4.33-r0 | — |
| Alpine v3.4 | apache2 | 2.4.33-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | httpd +5 | 2.4.6-93.0.1.el7 | ELSA-2020-1121 |
| Oracle Linux 7 | mod_ssl +1 | 1:2.4.6-93.0.1.el7 | ELSA-2020-1121 |
Advisories 14
- RHSA-2020:1121 Red Hat Security Advisory: httpd security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2019:0367 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.29 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2018:3558 Red Hat Security Advisory: httpd24 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-3627-2 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3627-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4164-1 apache2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1389-1 apache2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2018:1161-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:0879-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:0901-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:1079-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:1161-2 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2023-1594 IBM Tivoli Network Manager: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 28, 2023
- ELSA-2020-1121 Moderate: httpd security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 6, 2020
References
- USN-3627-1 vendor-advisory
- 103512 vdb-entry
- DSA-4164 vendor-advisory
- https://security.netapp.com/advisory/ntap-20180601-0004/
- RHSA-2018:3558 vendor-advisory
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03909en_us
- RHSA-2019:0367 vendor-advisory
- USN-3627-2 vendor-advisory
- [oss-security] 20180323 CVE-2017-15710: Out of bound write in mod_authnz_ldap when using too small Accept-Language values mailing-list
- 1040569 vdb-entry
- https://httpd.apache.org/security/vulnerabilities_24.html
- [debian-lts-announce] 20180530 [SECURITY] [DLA 1389-1] apache2 security update mailing-list
- RHSA-2019:0366 vendor-advisory
- USN-3937-2 vendor-advisory
- [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
- https://www.tenable.com/security/tns-2019-09
- [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: r1073143 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/ 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: r1073149 [11/13] - 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