CVE-2026-34355
Apache HTTP Server: mod_proxy_html buffer overflow
No exploitation reported by the sources we read.
- Published2026-06-08
- Fixed in2.4.68
- WeaknessCWE-120 · CWE-122
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2026-06-0816:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-34355?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-34355?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 2.4 | ≥ 2.4.0, < 2.4.68 | 2.4.68 | NVD · OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Packages
- httpdAlmaLinux:10all versions · fixed in 2.4.63-13.el10_2.4and 8 other packages
- httpdAlmaLinux:9all versions · fixed in 2.4.62-13.el9_8.5and 8 other packages
- httpdAlmaLinux:8all versions · fixed in 2.4.37-65.module_el8.10.0+4233+8b7d9181.9and 5 other packages
- mod_http2AlmaLinux:8all versions · fixed in 1.15.7-10.module_el8.10.0+4233+8b7d9181.7
- mod_mdAlmaLinux:8all versions · fixed in 1:2.0.8-8.module_el8.10.0+4088+57f011c1.2
- mod_sslAlmaLinux:10all versions · fixed in 1:2.4.63-13.el10_2.4and 1 other package
- mod_sslAlmaLinux:9all versions · fixed in 1:2.4.62-13.el9_8.5and 1 other package
- mod_sslAlmaLinux:8all versions · fixed in 1:2.4.37-65.module_el8.10.0+4233+8b7d9181.9and 1 other package
Vendor advisories
httpd: Apache HTTP Server: Buffer overflow in mod_proxy_html allows security bypass
httpd as a component of Red Hat Enterprise Linux 6 · httpd-devel as a component of Red Hat Enterprise Linux 6 · httpd-manual as a component of Red Hat Enterprise Linux 6 · +12 more
Red Hat Security Advisory: httpd security update
Red Hat Security Advisory: httpd security update
Red Hat Security Advisory: httpd security update
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP5 security update
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP5 security update
6 more advisories
Fix
- Update Apache HTTP Server to 2.4.68
- Vendor fix Red Hat Product Security RHSA-2026:67152 · 5 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
- Vendor fix Red Hat Product Security RHSA-2026:56868 · 16 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
- Vendor fix Red Hat Product Security RHSA-2026:53371 · 2 productsThe Insights proxy container image provided here is downloaded by the Red Hat Insights proxy product RPM. Before applying this update, make sure all previously released errata relevant to your system have been applied.
- Vendor fix Red Hat Product Security RHSA-2026:25042 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
- Workaround from the vendor Red Hat Product Security RHSA-2026:67152 · 75 productsDisable 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 fo…
Advisories and patches
- httpd.apache.orgVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVE recordread 2026-10-23
- CISA-ADPSSVC decisionnone2026-06-08
- OpenCVESSVC decisionnone—
- CISA-ADPCVSS 3.17.52026-06-08
- CNACVSS 3.17.5read 2026-10-23
- CNAweakness (CWE)CWE-120, CWE-122read 2026-10-23
- FIRST EPSSEPSS score1.2 %2026-10-23
- OSVaffected packages—
- Microsoft MSRCadvisory—
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-06-08
- Last Modified
- 2026-09-14
- NVD status
- Modified
- MSRC Title
- Apache HTTP Server: mod_proxy_html buffer overflow
Frequently asked questions
What is CVE-2026-34355?
Is CVE-2026-34355 actively exploited?
What is the CVSS score for CVE-2026-34355?
Running Apache HTTP Server? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
No credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.