How severe is CVE-2020-27678?

CVE-2020-27678 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-2020-27678 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27678?

CVE-2020-27678 primarily affects Illumos. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-27678?

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-2020-27678 published?

CVE-2020-27678 was published on 2020-10-26 and last updated on 2026-06-17.

CVE-2020-27678

CVE-2020-27678 is a critical-severity vulnerability in Illumos 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-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (70th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Illumos
Published: 2020-10-26
Last modified: 2026-06-17

Description

An issue was discovered in illumos before 2020-10-22, as used in OmniOS before r151030by, r151032ay, and r151034y and SmartOS before 20201022. There is a buffer overflow in parse_user_name in lib/libpam/pam_framework.c.

Frequently asked questions

What is CVE-2020-27678?: An issue was discovered in illumos before 2020-10-22, as used in OmniOS before r151030by, r151032ay, and r151034y and SmartOS before 20201022. There is a buffer overflow in parse_user_name in lib/libpam/pam_framework.c.
How severe is CVE-2020-27678?: CVE-2020-27678 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-2020-27678 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (70th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27678?: CVE-2020-27678 primarily affects Illumos. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-27678?: 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-2020-27678 published?: CVE-2020-27678 was published on 2020-10-26 and last updated on 2026-06-17.

References

https://github.com/illumos/illumos-gate/commit/1d276e0b382cf066dae93640746d8b4c54d15452

Affected products (4)

cpe:2.3:o:illumos:illumos:*:*:*:*:*:*:*:*
cpe:2.3:o:joyent:smartos:*:*:*:*:*:*:*:*
cpe:2.3:o:omniosce:omnios:*:*:*:*:community:*:*:*
cpe:2.3:o:omniosce:omnios:*:*:*:*:*:*:*:*

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CVE-2021-43395 — Medium (CVSS 5.5): An issue was discovered in illumos before f859e7171bb5db34321e45585839c6c3200ebb90, OmniOS Community Edition r151038,…
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