Buffer overflow in Libssh2

CVE-2019-3863

A flaw was found in libssh2 before 1.8.1 creating a vulnerability on the SSH client side. A server could send a multiple keyboard interactive response messages whose total length are greater than unsigned char max characters. This value is used by the SSH client as an index to copy memory causing in an out of bounds memory write error.

Vulnerability class: Integer Overflow

EPSS: 0.034 (87.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2019-3863?
CVE-2019-3863 is a high-severity vulnerability in Libssh2, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2019-03-25.
How severe is CVE-2019-3863?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2019-3863 known to be exploited?
6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.