Vulnerability in Apache HTTP Server

CVE-2009-3555

The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft Internet Information Services (IIS) 7.0, mod_ssl in the Apache HTTP Server 2.2.14 and earlier, OpenSSL before 0.9.8l, GnuTLS 2.8.5 and earlier, Mozilla Network Security Services (NSS) 3.12.4 and earlier, multiple Cisco products, and other products, does not properly associate renegotiation handshakes with an existing connection, which allows man-in-the-middle attackers to insert data into HTTPS sessions, and possibly other types of sessions protected by TLS or SSL, by sending an unauthenticated request that is processed retroactively by a server in a post-renegotiation context, related to a "plaintext injection" attack, aka the "Project Mogul" issue.

Vulnerability class: Improper Certificate Validation

EPSS: 0.873 (99.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2009-3555?
CVE-2009-3555 is a critical-severity vulnerability in Apache HTTP Server, classified under Improper Certificate Validation. CVSS score: 9.8/10. Published 2009-11-09.
How severe is CVE-2009-3555?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2009-3555 known to be exploited?
40 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.