How severe is CVE-2020-10933?

CVE-2020-10933 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-2020-10933 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-10933?

CVE-2020-10933 primarily affects Ruby-lang Ruby. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-10933?

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

When was CVE-2020-10933 published?

CVE-2020-10933 was published on 2020-05-04 and last updated on 2026-06-17.

CVE-2020-10933

CVE-2020-10933 is a medium-severity vulnerability in Ruby-lang Ruby 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-908.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 3% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-908
Affected product: Ruby-lang Ruby
Published: 2020-05-04
Last modified: 2026-06-17

Description

An issue was discovered in Ruby 2.5.x through 2.5.7, 2.6.x through 2.6.5, and 2.7.0. If a victim calls BasicSocket#read_nonblock(requested_size, buffer, exception: false), the method resizes the buffer to fit the requested size, but no data is copied. Thus, the buffer string provides the previous value of the heap. This may expose possibly sensitive data from the interpreter.

Frequently asked questions

What is CVE-2020-10933?: An issue was discovered in Ruby 2.5.x through 2.5.7, 2.6.x through 2.6.5, and 2.7.0. If a victim calls BasicSocket#read_nonblock(requested_size, buffer, exception: false), the method resizes the buffer to fit the requested size, but no data is copied. Thus, the buffer string provides the previous value of the heap. This may expose possibly sensitive data from the interpreter.
How severe is CVE-2020-10933?: CVE-2020-10933 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-2020-10933 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-10933?: CVE-2020-10933 primarily affects Ruby-lang Ruby. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-10933?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-10933 published?: CVE-2020-10933 was published on 2020-05-04 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
cpe:2.3:a:ruby-lang:ruby:2.7.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

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