CVE-2009-3555: The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft Internet Information Ser

Q: How do I fix CVE-2009-3555?

http server: upgrade to newer than 2.2.14; gnutls: upgrade to newer than 2.8.5; nss: upgrade to newer than 3.12.4. Exact commands for each OS are on this page.

Q: Is CVE-2009-3555 being exploited?

CVE-2009-3555 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2009-3555 affect?

CVE-2009-3555 affects http server, gnutls, nss. Severity is critical (CVSS 9.8). 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 Ne

Q: How urgent is CVE-2009-3555?

Priority 77/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2009-3555 is a critical-severity flaw (CVSS 9.8) affecting http server, gnutls, nss. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 at

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	87.3% (top 1%)
CISA exploited list	No
Weakness	CWE-295, CWE-300
Published	2009-11-09
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: apache · canonical · debian · gnu · mozilla · openssl

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2009-11-09 17:30 UTCPublished CVE record published
2026-06-16 23:11 UTCUpdated Record last modified

apache http server UPGRADE

Affected: <= 2.2.14

Fixed in: newer than 2.2.14

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy http-server || rpm -q http-server || http-server --version

2. UPGRADE to newer than 2.2.14 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade http-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade http-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

gnu gnutls UPGRADE

Affected: <= 2.8.5

Fixed in: newer than 2.8.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy gnutls || rpm -q gnutls || gnutls --version

2. UPGRADE to newer than 2.8.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade gnutls

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade gnutls

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

mozilla nss UPGRADE

Affected: <= 3.12.4

Fixed in: newer than 3.12.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nss || rpm -q nss || nss --version

2. UPGRADE to newer than 3.12.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nss

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nss

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

openssl openssl UPGRADE

Affected: <= 0.9.8k · 1.0

Fixed in: newer than 0.9.8k

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openssl || rpm -q openssl || openssl --version

2. UPGRADE to newer than 0.9.8k (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openssl

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openssl

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

canonical ubuntu linux MITIGATE

Affected: 8.04 · 8.10 · 9.04 · 9.10 · 10.04 · 10.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 4.0 · 5.0 · 6.0 · 7.0 · 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Maven · org.apache.tomcat:tomcat · FIXED · 7.0.10 · vulnerable: >= 7.0.0, < 7.0.10 · source

Set org.apache.tomcat:tomcat to 7.0.10 or later in pom.xml or build.gradle, then rebuild and redeploy.

Fedora 46 · rust-ingredients · FIXED · 0.3.3-2.fc46 · FEDORA-2026-0b3d9feffd · source

sudo dnf upgrade --advisory=FEDORA-2026-0b3d9feffd

Fedora ELN · dpkg · FIXED · 1.23.11-2.eln159 · FEDORA-2026-732e4ac21b · source

sudo dnf upgrade --advisory=FEDORA-2026-732e4ac21b

Debian 12 · apache2 · FIXED · 2.2.14-2

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.2.14-2" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · apache2 · FIXED · 2.2.14-2

sudo apt update && sudo apt install --only-upgrade apache2 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' apache2)" ge "2.2.14-2" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · lighttpd · FIXED · 1.4.30-1

sudo apt update && sudo apt install --only-upgrade lighttpd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lighttpd)" ge "1.4.30-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · lighttpd · FIXED · 1.4.30-1

sudo apt update && sudo apt install --only-upgrade lighttpd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' lighttpd)" ge "1.4.30-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 3 · httpd · FIXED · httpd-2.0.46-77.ent

sudo dnf upgrade --advisory=RHSA-2009:1579 rpm -q httpd

RHEL 3 · openssl · FIXED · openssl-0.9.7a-33.26

sudo dnf upgrade --advisory=RHSA-2010:0163 rpm -q openssl

RHEL 4 · httpd · FIXED · httpd-2.0.52-41.ent.6

sudo dnf upgrade --advisory=RHSA-2009:1580 rpm -q httpd

RHEL 4 · openssl · FIXED · openssl-0.9.7a-43.17.el4_8.5

sudo dnf upgrade --advisory=RHSA-2010:0163 rpm -q openssl

RHEL 4 · nspr · FIXED · nspr-4.8.4-1.1.el4_8

sudo dnf upgrade --advisory=RHSA-2010:0165 rpm -q nspr

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: johnwchadwick/cve-2009-3555-test-server (3 stars)
Write-up: h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05150888
Write-up: oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A8535
Exploit-DB: Mozilla NSS - NULL Character CA SSL Certificate Validation Security Bypass
Exploit-DB: TLS - Renegotiation

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2009-3555?

http server: upgrade to newer than 2.2.14; gnutls: upgrade to newer than 2.8.5; nss: upgrade to newer than 3.12.4. Exact commands for each OS are on this page.

Is CVE-2009-3555 being exploited?

CVE-2009-3555 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2009-3555 affect?

CVE-2009-3555 affects http server, gnutls, nss. Severity is critical (CVSS 9.8). 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 Ne

How urgent is CVE-2009-3555?

Priority 77/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

OpenSSL vulnerabilities · Apache HTTP Server vulnerabilities · Ubuntu vulnerabilities · Debian vulnerabilities · Cisco vulnerabilities · GnuTLS vulnerabilities

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References

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