Is CVE-2026-3731 in the CISA KEV catalog?

No. CVE-2026-3731 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-3731?

CVE-2026-3731 has a CVSS v3 base score of 5.3 (Moderate).

What is the EPSS score for CVE-2026-3731?

CVE-2026-3731 has an EPSS score of 0.63% (46th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-3731?

Upgrade libssh on debian unstable to 0.12.0-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2026-3731

MEDIUM

5.3

CVSS v3

NVD

Description

A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected component.

CWE-119Buffer Overflow CWE-125Out-of-bounds Read

How to fix

Remediation Available

libsshDebian

Fixed in:0.12.0-1CVE-2026-3731

libsshUbuntu

Fixed in:0.6.3-4.3ubuntu0.6+esm5USN-8093-1

Fixed in:0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7USN-8093-1

Fixed in:0.9.3-2ubuntu2.5+esm4USN-8093-1

Fixed in:0.9.6-2ubuntu0.22.04.7USN-8093-1

Fixed in:0.10.6-2ubuntu0.4USN-8093-1

Fixed in:0.11.2-1ubuntu0.3USN-8093-1

libssh-4Ubuntu

Fixed in:0.6.3-4.3ubuntu0.6+esm5USN-8093-1

Fixed in:0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7USN-8093-1

Fixed in:0.9.3-2ubuntu2.5+esm4USN-8093-1

Fixed in:0.9.6-2ubuntu0.22.04.7USN-8093-1

Fixed in:0.10.6-2ubuntu0.4USN-8093-1

Fixed in:0.11.2-1ubuntu0.3USN-8093-1

libssh-gcrypt-4Ubuntu

Fixed in:0.6.3-4.3ubuntu0.6+esm5USN-8093-1

Fixed in:0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7USN-8093-1

Fixed in:0.9.3-2ubuntu2.5+esm4USN-8093-1

Fixed in:0.9.6-2ubuntu0.22.04.7USN-8093-1

Fixed in:0.10.6-2ubuntu0.4USN-8093-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:X/RL:O/RC:C

Exploit Intelligence

0.63%probability of exploitation in 30 days

46thpercentile

Moderate risk: more likely to be exploited than 46% of all known CVEs.

References

Patch2

Third-Party Advisory2

VDB Entry1

vuldb.com

Product1

libssh.org

Related Vulnerabilities

Other CWE-119 (Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-4966	Critical	9.4	100%	KEV + Ransom	Fix
CVE-2017-11882	High	7.8	100%	KEV + Ransom	-
CVE-2020-0796	Critical	10.0	100%	KEV + Ransom	-
CVE-2008-4250	Critical	9.8	99%	KEV	-
CVE-2017-15944	Critical	9.8	98%	KEV	Fix
CVE-2015-0014	High	10.0	97%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-12.