How severe is CVE-2009-0256?

CVE-2009-0256 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2009-0256 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-0256?

CVE-2009-0256 primarily affects Typo3. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-0256?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2009-0256 published?

CVE-2009-0256 was published on 2009-01-22 and last updated on 2026-06-16.

CVE-2009-0256

CVE-2009-0256 is a high-severity vulnerability in Typo3 with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Typo3
Published: 2009-01-22
Last modified: 2026-06-16

Description

Session fixation vulnerability in the authentication library in TYPO3 4.0.0 through 4.0.9, 4.1.0 through 4.1.7, and 4.2.0 through 4.2.3 allows remote attackers to hijack web sessions via unspecified vectors related to (1) frontend and (2) backend authentication.

Frequently asked questions

What is CVE-2009-0256?: Session fixation vulnerability in the authentication library in TYPO3 4.0.0 through 4.0.9, 4.1.0 through 4.1.7, and 4.2.0 through 4.2.3 allows remote attackers to hijack web sessions via unspecified vectors related to (1) frontend and (2) backend authentication.
How severe is CVE-2009-0256?: CVE-2009-0256 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2009-0256 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0256?: CVE-2009-0256 primarily affects Typo3. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-0256?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2009-0256 published?: CVE-2009-0256 was published on 2009-01-22 and last updated on 2026-06-16.

References

Affected products (24)

cpe:2.3:a:typo3:typo3:4.0:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.1:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.2:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.3:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.4:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.5:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.6:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.7:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.8:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.0.9:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.0:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.0:beta1:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.0:rc1:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.1:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.2:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.3:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.4:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.5:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.6:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.1.7:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.2.0:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.2.1:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.2.2:*:*:*:*:*:*:*
cpe:2.3:a:typo3:typo3:4.2.3:*:*:*:*:*:*:*

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Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

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