How severe is CVE-2009-3555?

CVE-2009-3555 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2009-3555?

CVE-2009-3555 affects the following packages: org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven). Ecosystems affected: Maven.

How do I fix CVE-2009-3555?

Update org.apache.tomcat:tomcat to 7.0.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-3555 is resolved across your whole dependency graph.

How do I detect CVE-2009-3555 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2009-3555 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2009-3555?

O3 pinpoints whether CVE-2009-3555 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2009-3555 actively exploited in the wild?

Yes. There are 7 known exploit references for CVE-2009-3555, including 2 documented proof-of-concept exploits on Exploit-DB and 4 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2009-3555?

CVE-2009-3555 has an EPSS (Exploit Prediction Scoring System) score of 87.3%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2009-3555?

CVE-2009-3555 is classified as CWE-295 (CWE-295), CWE-300 (CWE-300). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2009-3555 published, and has it been updated?

CVE-2009-3555 was published on November 9, 2009 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2009-3555: tomcat (Critical 9.8)

EPSS Exploitation Probability

via FIRST.org ↗

87.3%probability of exploitation in next 30 days

Very High Risk100th percentile+83.52%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

3 pkgs affected

☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.tomcat:tomcat`	≥ 7.0.0&&< 7.0.10	7.0.10
☕Maven	`org.apache.tomcat:tomcat`	≥ 6.0.0&&< 6.0.32	6.0.32
☕Maven	`org.apache.tomcat:tomcat`	≥ 5.0.0&&< 5.5.33	5.5.33

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.apache.tomcat:tomcat to 7.0.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2009-3555 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2009-3555 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2009-3555. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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 i

O3 Security · Impact-Aware SCA

Is CVE-2009-3555 in your dependencies?

O3 detects CVE-2009-3555 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2009-3555