CVE-2026-34356
Apache HTTP Server: ProxyPassReverseCookieMap buffer overflow
No exploitation reported by the sources we read.
- Published2026-06-08
- Fixed in2.4.68
- WeaknessCWE-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
Heap-based Buffer Overflow vulnerability in Apache HTTP Server with malicious backend servers and ProxyPassReverseCookie* This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.
Timeline
dates in UTC- 2026-06-0816:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 15:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-34356?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-34356?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: Heap-based Buffer Overflow via malicious backend servers
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 productsTo prevent this denial-of-service flaw, ensure your Apache proxy rules only connect to highly trusted backend servers. If you must proxy traffic to unverified or external backends, disable the cookie-rewriting features. Steps to Mitigate: Open your Apache configuration file (e.g., /etc/httpd/conf…
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
- CNAweakness (CWE)CWE-122read 2026-10-23
- FIRST EPSSEPSS score1.2 %2026-10-22
- 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
- 2026-07-23
- NVD status
- Analyzed
- MSRC Title
- Apache HTTP Server: ProxyPassReverseCookieMap buffer overflow
Frequently asked questions
What is CVE-2026-34356?
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What is the CVSS score for CVE-2026-34356?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.