How severe is CVE-2026-22903?

CVE-2026-22903 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-22903 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-22903?

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

Does CVE-2026-22903 have an EU (EUVD) identifier?

Yes. CVE-2026-22903 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6925.

When was CVE-2026-22903 published?

CVE-2026-22903 was published on 2026-02-09 and last updated on 2026-06-17.

CVE-2026-22903

CVE-2026-22903 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. 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-121.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-6925
Weakness: CWE-121
Published: 2026-02-09
Last modified: 2026-06-17

Description

An unauthenticated remote attacker can send a crafted HTTP request containing an overly long SESSIONID cookie. This can trigger a stack buffer overflow in the modified lighttpd server, causing it to crash and potentially enabling remote code execution due to missing stack protections.

Frequently asked questions

What is CVE-2026-22903?: An unauthenticated remote attacker can send a crafted HTTP request containing an overly long SESSIONID cookie. This can trigger a stack buffer overflow in the modified lighttpd server, causing it to crash and potentially enabling remote code execution due to missing stack protections.
How severe is CVE-2026-22903?: CVE-2026-22903 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-22903 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-22903?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-22903 have an EU (EUVD) identifier?: Yes. CVE-2026-22903 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-6925.
When was CVE-2026-22903 published?: CVE-2026-22903 was published on 2026-02-09 and last updated on 2026-06-17.

References

https://certvde.com/de/advisories/VDE-2026-004

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