How severe is CVE-2013-4421?

CVE-2013-4421 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2013-4421 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2013-4421?

CVE-2013-4421 affects Dropbear Ssh Project Dropbear Ssh. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2013-4421?

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

When was CVE-2013-4421 published?

CVE-2013-4421 was published on 2013-10-25 and last updated on 2026-06-16.

CVE-2013-4421

CVE-2013-4421 is a medium-severity vulnerability in Dropbear Ssh Project Dropbear Ssh with a CVSS 2.0 base score of 5.0. 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-189.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 6% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-189
Affected product: Dropbear Ssh Project Dropbear Ssh
Published: 2013-10-25
Last modified: 2026-06-16

Description

The buf_decompress function in packet.c in Dropbear SSH Server before 2013.59 allows remote attackers to cause a denial of service (memory consumption) via a compressed packet that has a large size when it is decompressed.

Frequently asked questions

What is CVE-2013-4421?: The buf_decompress function in packet.c in Dropbear SSH Server before 2013.59 allows remote attackers to cause a denial of service (memory consumption) via a compressed packet that has a large size when it is decompressed.
How severe is CVE-2013-4421?: CVE-2013-4421 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2013-4421 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2013-4421?: CVE-2013-4421 affects Dropbear Ssh Project Dropbear Ssh. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2013-4421?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2013-4421 published?: CVE-2013-4421 was published on 2013-10-25 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:dropbear_ssh_project:dropbear_ssh:*:*:*:*:*:*:*:*

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