How severe is CVE-2021-3978?

CVE-2021-3978 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3978 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3978?

CVE-2021-3978 affects Cloudflare Octorpki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3978?

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.

Does CVE-2021-3978 have an EU (EUVD) identifier?

Yes. CVE-2021-3978 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-2286.

When was CVE-2021-3978 published?

CVE-2021-3978 was published on 2025-01-29 and last updated on 2026-06-17.

CVE-2021-3978

CVE-2021-3978 is a high-severity vulnerability in Cloudflare Octorpki with a CVSS 3.x base score of 7.5. 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-269.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-2286
Weakness: CWE-269
Affected product: Cloudflare Octorpki
Published: 2025-01-29
Last modified: 2026-06-17

Description

When copying files with rsync, octorpki uses the "-a" flag 0, which forces rsync to copy binaries with the suid bit set as root. Since the provided service definition defaults to root ( https://github.com/cloudflare/cfrpki/blob/master/package/octorpki.service ) this could allow for a vector, when combined with another vulnerability that causes octorpki to process a malicious TAL file, for a local privilege escalation.

Frequently asked questions

What is CVE-2021-3978?: When copying files with rsync, octorpki uses the "-a" flag 0, which forces rsync to copy binaries with the suid bit set as root. Since the provided service definition defaults to root ( https://github.com/cloudflare/cfrpki/blob/master/package/octorpki.service ) this could allow for a vector, when combined with another vulnerability that causes octorpki to process a malicious TAL file, for a local privilege escalation.
How severe is CVE-2021-3978?: CVE-2021-3978 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3978 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3978?: CVE-2021-3978 affects Cloudflare Octorpki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3978?: 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.
Does CVE-2021-3978 have an EU (EUVD) identifier?: Yes. CVE-2021-3978 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-2286.
When was CVE-2021-3978 published?: CVE-2021-3978 was published on 2025-01-29 and last updated on 2026-06-17.

References

https://github.com/cloudflare/cfrpki/security/advisories/GHSA-3pqh-p72c-fj85

Affected products (1)

cpe:2.3:a:cloudflare:octorpki:*:*:*:*:*:*:*:*

More vulnerabilities in Cloudflare Octorpki

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