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CVE-2026-34356 Apache CVE debrief

CVE-2026-34356 is a Heap-based Buffer Overflow vulnerability in Apache HTTP Server. The vulnerability occurs with malicious backend servers and ProxyPassReverseCookie*. The issue affects Apache HTTP Server versions from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue. The CVSS score for this vulnerability is 7.5, and the severity is classified as HIGH.

Vendor
Apache
Product
HTTP Server
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-08
Original CVE updated
2026-07-23
Advisory published
2026-06-08
Advisory updated
2026-07-23

Who should care

Users of Apache HTTP Server versions 2.4.0 through 2.4.67 should be aware of this vulnerability and take necessary actions to mitigate the risk.

Technical summary

The vulnerability is caused by a Heap-based Buffer Overflow in Apache HTTP Server. This can occur when the server is configured with malicious backend servers and ProxyPassReverseCookie*.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade to Apache HTTP Server version 2.4.68 or later.
  • Refer to the vendor advisory for more information: [ref-4](https://httpd.apache.org/security/vulnerabilities_24.html)

Evidence notes

The CVE record [cve-org] and NVD detail [nvd] provide additional information about this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-34356 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-34356

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-34356 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-34356

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.