CVE-2023-43622

Apache HTTP Server: DoS in HTTP/2 with initial windows size 0

Description

An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue.

Scores

Weaknesses (CWE)

• CWE-400

European references

• ENISA EUVD · EUVD-2023-48022
• GCVE · GCVE-0-2023-43622

CERT-FR advisories

• CERTFR-2026-AVI-1355 — Multiples vulnérabilités dans Oracle Weblogic · cert.ssi.gouv.fr
• CERTFR-2024-AVI-0672 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
• CERTFR-2023-AVI-1033 — Multiples vulnérabilités dans Tenable Security Center · cert.ssi.gouv.fr
• CERTFR-2023-AVI-0966 — Multiples vulnérabilités dans Tenable Security Center · cert.ssi.gouv.fr
• CERTFR-2023-AVI-0868 — Multiples vulnérabilités dans Apache HTTP Server · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

• cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* ≥ 2.4.55 < 2.4.58

Affected products

References

• https://httpd.apache.org/security/vulnerabilities_24.html
• https://security.netapp.com/advisory/ntap-20231027-0011/

Sources