How severe is CVE-2026-103276?

CVE-2026-103276 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-103276 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-103276?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-103276 published?

CVE-2026-103276 was published on 2026-10-01.

CVE-2026-103276

CVE-2026-103276 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. 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-173.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v4: 6.9
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-173
Published: 2026-10-01
Last modified: 2026-10-01

Description

Ghost versions before 6.20.0 contain a file extension filtering bypass vulnerability that allows unauthenticated attackers to read theme templates and metadata. Attackers can use URL encoding to bypass extension validation and access sensitive theme files.

Frequently asked questions

What is CVE-2026-103276?: Ghost versions before 6.20.0 contain a file extension filtering bypass vulnerability that allows unauthenticated attackers to read theme templates and metadata. Attackers can use URL encoding to bypass extension validation and access sensitive theme files.
How severe is CVE-2026-103276?: CVE-2026-103276 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-103276 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-103276?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-103276 published?: CVE-2026-103276 was published on 2026-10-01.

References

Other CWE-173 vulnerabilities

CVE-2026-10050 — Critical (CVSS 9.1): In Eclipse Jetty, the Digest authentication server-side component uses ISO-8859-1 to encode the password as…
CVE-2026-19611 — High (CVSS 7.4): A flaw was found in WildFly Elytron. Password hashing and verification normalize input with Unicode NFKC, which can…
CVE-2023-26303 — Low (CVSS 3.3): Denial of service could be caused to markdown-it-py, before v2.2.0, if an attacker was allowed to force null assertions…
CVE-2023-26302 — Low (CVSS 3.3): Denial of service could be caused to the command line interface of markdown-it-py, before v2.2.0, if an attacker was…
CVE-2026-81638 — Low (CVSS 2.1): Improper Handling of Alternate Encoding vulnerability in ash-project ash_double_entry allows an attacker to submit…

Browse all CWE-173 vulnerabilities →