CVE-2009-3555

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.

Exploit odds

87.3% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2009-10-05 00:00 UTC ReservedThe CVE id was reserved by its CNA
2. 2009-11-09 17:30 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-06-16 23:11 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 87.3% in the next 30 days (EPSS).
• Severity: 9.8 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.
• It meets the bar for Drop everything: critical, and exploited or very likely to be.

Details

Published

2009-11-09 17:30 UTC

Last modified

2026-06-16 23:11 UTC

Exploit probability

87.3% · EPSS, next 30 days

Weakness

CWE-295 · Improper certificate validation

Record status

Modified

Affected

• Apache Http Server ≤ 2.2.14
• Gnu Gnutls ≤ 2.8.5
• Mozilla Nss ≤ 3.12.4
• OpenSSL ≤ 0.9.8k
• OpenSSL 1.0
• Canonical Ubuntu Linux 8.04
• Canonical Ubuntu Linux 8.10
• Canonical Ubuntu Linux 9.04

Attack profile CVSS 3.1 · 9.8

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2009-3555.md and follow it. Check whether this project is affected by CVE-2009-3555. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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