CVE-2009-3555
CRITICALEPSS 100th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
References
- blog.g-sec.lu
- blogs.sun.com
- kbase.redhat.com
- lists.apple.com
- lists.apple.com
- lists.apple.com
- lists.fedoraproject.org
- lists.fedoraproject.org
- lists.fedoraproject.org
- lists.fedoraproject.org
- lists.fedoraproject.org
- lists.fedoraproject.org
- lists.gnu.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- lists.opensuse.org
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- marc.info
- openbsd.org
- openbsd.org
- seclists.org
- secunia.com
Related Vulnerabilities
Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2015-4000 | Low | 3.7 | 100% | - | Fix |
| CVE-2020-0601 | High | 8.1 | 89% | KEV | Fix |
| CVE-2022-26923 | High | 8.8 | 83% | KEV | Fix |
| CVE-2023-27823 | Critical | 9.8 | 53% | - | - |
| CVE-2022-42979 | High | 8.8 | 24% | - | - |
| CVE-2018-8034 | High | 7.5 | 21% | - | Fix |
Common questions
How do I fix CVE-2009-3555?
Upgrade apache2 on debian 11 to 2.2.14-2 or later.
Is CVE-2009-3555 being actively exploited?
Not that we know of. CVE-2009-3555 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 87.3% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.
How severe is CVE-2009-3555?
CVE-2009-3555 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2009-3555 affect?
Published advisories record a fix for apache2 (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2009-3555
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-27.