How severe is CVE-2020-9366?

CVE-2020-9366 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-2020-9366 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-9366?

CVE-2020-9366 affects Gnu Screen. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-9366?

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.

When was CVE-2020-9366 published?

CVE-2020-9366 was published on 2020-02-24 and last updated on 2026-06-17.

CVE-2020-9366

CVE-2020-9366 is a critical-severity vulnerability in Gnu Screen 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Gnu Screen
Published: 2020-02-24
Last modified: 2026-06-17

Description

A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.

Frequently asked questions

What is CVE-2020-9366?: A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Specially crafted output, or a special program, could corrupt memory and crash Screen or possibly have unspecified other impact.
How severe is CVE-2020-9366?: CVE-2020-9366 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-2020-9366 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-9366?: CVE-2020-9366 affects Gnu Screen. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-9366?: 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.
When was CVE-2020-9366 published?: CVE-2020-9366 was published on 2020-02-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:gnu:screen:*:*:*:*:*:*:*:*

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