Is CVE-2026-48840 in the CISA KEV catalog?

No. CVE-2026-48840 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-48840?

CVE-2026-48840 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-48840?

CVE-2026-48840 has an EPSS score of 0.26% (18th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-48840?

Upgrade exim4 on debian 11 to 4.94.2-7+deb11u6 or later. Fixes are available for 7 affected products.

CVE & CISA-KEV Catalog

CVE-2026-48840

MEDIUM

5.3

CVSS v3

NVD

Description

Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memory values to a client.

CWE-839

How to fix

Remediation Available

exim4Debian

Fixed in:4.94.2-7+deb11u6CVE-2026-48840

Fixed in:4.96-15+deb12u10CVE-2026-48840

Fixed in:4.98.2-1+deb13u3CVE-2026-48840

Fixed in:4.99.3-2CVE-2026-48840

exim4Ubuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

Fixed in:4.95-4ubuntu2.9USN-8353-1

Fixed in:4.97-4ubuntu4.6USN-8353-1

Fixed in:4.98.2-1ubuntu2.3USN-8353-1

exim4-baseUbuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

Fixed in:4.95-4ubuntu2.9USN-8353-1

Fixed in:4.97-4ubuntu4.6USN-8353-1

Fixed in:4.98.2-1ubuntu2.3USN-8353-1

exim4-daemon-heavyUbuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

exim4-daemon-lightUbuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

exim4-devUbuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

eximon4Ubuntu

Fixed in:4.82-3ubuntu2.4+esm9USN-8382-1

Fixed in:4.86.2-2ubuntu2.6+esm9USN-8382-1

Fixed in:4.90.1-1ubuntu1.10+esm6USN-8382-1

Fixed in:4.93-13ubuntu1.12+esm1USN-8382-1

Fixed in:4.95-4ubuntu2.9USN-8353-1

Fixed in:4.97-4ubuntu4.6USN-8353-1

Fixed in:4.98.2-1ubuntu2.3USN-8353-1

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

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.26%probability of exploitation in 30 days

18thpercentile

Low risk: more likely to be exploited than 18% of all known CVEs.

References

Vendor Advisory1

exim.org

Mitigation2

Other references1

lists.debian.org

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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 2026-06-05.