Apache HTTP Server: mod_proxy_html buffer overflow
Summary
| CVE | CVE-2026-34355 |
|---|---|
| State | PUBLISHED |
| Assigner | apache |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-08 16:16:38 UTC |
| Updated | 2026-07-23 07:10:00 UTC |
| Description | A buffer overflow in mod_proxy_html in Apache HTTP Server 2.4.67 and earlier allows an attack by an untrusted backend. Users are recommended to upgrade to version 2.4.68, which fixes this issue. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.009370000 probability, percentile 0.571350000 (date 2026-07-22)
Problem Types: CWE-122 | CWE-120 | CWE-122 CWE-122 Heap-based Buffer Overflow | CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Apache | Http Server | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Apache Software Foundation | Apache HTTP Server | affected 2.4.0 2.4.67 semver | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 10 | unaffected 0:2.4.63-13.el10_2.4 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 8 | unaffected 8100020260714175253.489197e6 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 9 | unaffected 0:2.4.62-13.el9_8.5 * rpm | Not specified |
| ADP | Red Hat | Red Hat Hardened Images | unaffected 2.4.68-1.hum1 * rpm | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 7 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-34355 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| www.openwall.com/lists/oss-security/2026/06/08/6 | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List |
| httpd.apache.org/security/vulnerabilities_24.html | [email protected] | httpd.apache.org | Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:25042 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:41906 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34355.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:42828 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:34109 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Elhanan Haenel (en)
CNA: Junhui Lee (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-21T09:59:00.000Z | Report received |
| CNA | 2026-06-04T12:00:00.000Z | fixed in 2.4.x by r1934977 |
| CNA | 2026-06-08T12:00:00.000Z | 2.4.68 released |
| ADP | 2026-06-08T16:02:27.677Z | Reported to Red Hat. |
| ADP | 2026-06-08T15:20:30.900Z | Made public. |
Solutions
ADP: RHSA-2026:34109: Red Hat Enterprise Linux AppStream (v. 10)
ADP: RHSA-2026:42828: Red Hat Enterprise Linux AppStream (v. 8)
ADP: RHSA-2026:41906: Red Hat Enterprise Linux AppStream (v. 9)
ADP: RHSA-2026:25042: Red Hat Hardened Images
Workarounds
ADP: Disable the `mod_proxy_html` module if it is not essential for your Apache HTTP Server configuration. If `mod_proxy_html` is required, restrict its use to trusted backend servers only, employing network segmentation and access controls. After modifying the configuration, reload the httpd service for changes to apply, which may cause a brief service interruption. Steps to disable: Open /etc/httpd/conf.modules.d/00-proxy.conf. Add a # to comment out the line: LoadModule proxy_html_module modules/mod_proxy_html.so Verify configuration syntax: apachectl configtest Apply the change gracefully: systemctl reload httpd