How severe is CVE-2021-27343?

CVE-2021-27343 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-27343 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27343?

CVE-2021-27343 affects Serenityos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27343?

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-2021-27343 published?

CVE-2021-27343 was published on 2021-04-06 and last updated on 2026-06-17.

CVE-2021-27343

CVE-2021-27343 is a high-severity vulnerability in Serenityos 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-120.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Serenityos
Published: 2021-04-06
Last modified: 2026-06-17

Description

SerenityOS Unspecified is affected by: Buffer Overflow. The impact is: obtain sensitive information (context-dependent). The component is: /Userland/Libraries/LibCrypto/ASN1/DER.h Crypto::der_decode_sequence() function. The attack vector is: Parsing RSA Key ASN.1.

Frequently asked questions

What is CVE-2021-27343?: SerenityOS Unspecified is affected by: Buffer Overflow. The impact is: obtain sensitive information (context-dependent). The component is: /Userland/Libraries/LibCrypto/ASN1/DER.h Crypto::der_decode_sequence() function. The attack vector is: Parsing RSA Key ASN.1.
How severe is CVE-2021-27343?: CVE-2021-27343 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-27343 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27343?: CVE-2021-27343 affects Serenityos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27343?: 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-2021-27343 published?: CVE-2021-27343 was published on 2021-04-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:serenityos:serenityos:-:*:*:*:*:*:*:*

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