CVE-2026-34355

HIGH

Published Jun 8, 2026 Modified Jun 9, 2026 CWE-122

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.

CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0081

Probability of exploitation

0.52%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

Affected Products

Vendor	Product	Versions
apache	http_server	2.4.0 — 2.4.68

References

Advisories & Patches

https://httpd.apache.org/security/vulnerabilities_24.html

Other References

http://www.openwall.com/lists/oss-security/2026/06/08/6

Frequently Asked Questions

What is CVE-2026-34355? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-34355? +

CVE-2026-34355 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0081, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-34355? +

CVE-2026-34355 affects products from apache, specifically: http_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-34355? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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