How severe is CVE-2020-15904?

CVE-2020-15904 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-15904 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15904?

CVE-2020-15904 affects Pypi Bsdiff4. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-15904?

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-2020-15904 published?

CVE-2020-15904 was published on 2020-07-22 and last updated on 2026-06-17.

CVE-2020-15904

CVE-2020-15904 is a high-severity vulnerability in Pypi Bsdiff4 with a CVSS 3.x base score of 7.8. 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: High (CVSS 3.x base score 7.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Pypi Bsdiff4
Published: 2020-07-22
Last modified: 2026-06-17

Description

A buffer overflow in the patching routine of bsdiff4 before 1.2.0 allows an attacker to write to heap memory (beyond allocated bounds) via a crafted patch file.

Frequently asked questions

What is CVE-2020-15904?: A buffer overflow in the patching routine of bsdiff4 before 1.2.0 allows an attacker to write to heap memory (beyond allocated bounds) via a crafted patch file.
How severe is CVE-2020-15904?: CVE-2020-15904 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-15904 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15904?: CVE-2020-15904 affects Pypi Bsdiff4. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-15904?: 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-2020-15904 published?: CVE-2020-15904 was published on 2020-07-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:pypi:bsdiff4:*:*:*:*:*:*:*:*

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