CVE-2018-9860

HIGHEPSS 71th pctl

7.5

CVSS v3

Description

An issue was discovered in Botan 1.11.32 through 2.x before 2.6.0. An off-by-one error when processing malformed TLS-CBC ciphertext could cause the receiving side to include in the HMAC computation exactly 64K bytes of data following the record buffer, aka an over-read. The MAC comparison will subsequently fail and the connection will be closed. This could be used for denial of service. No information leak occurs.

CWE-193

How to fix

Remediation Available

botanDebian

Fixed in:2.4.0-6CVE-2018-9860

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

1.38%probability of exploitation in 30 days

71stpercentile

Elevated risk: more likely to be exploited than 71% of all known CVEs.

References

Vendor Advisory1

botan.randombit.net

Issue Tracking1

bugs.chromium.org

Related Vulnerabilities

Other CWE-193 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-3156	High	7.8	100%	KEV	Fix
CVE-2003-0466	Critical	9.8	78%	-	-
CVE-2023-44444	High	7.8	56%	-	Fix
CVE-2021-23017	High	7.7	53%	-	Fix
CVE-2023-28709	High	7.5	48%	-	Fix
CVE-2018-8828	Critical	9.8	30%	-	Fix

Common questions

How do I fix CVE-2018-9860?

Upgrade botan on debian 12 to 2.4.0-6 or later.

Is CVE-2018-9860 being actively exploited?

Not that we know of. CVE-2018-9860 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.4% is the estimated probability that it will be exploited in the next 30 days. That is higher than 71% of all scored CVEs.

How severe is CVE-2018-9860?

CVE-2018-9860 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2018-9860 affect?

Published advisories record a fix for botan (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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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 2026-06-17.