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Fencer Vulns
medium 5.3

CVE-2026-48840 json

Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memo…

published 2026-05-30 5 mo ago modified 2026-07-22 3 mo ago also EUVD-2026-33446

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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.

Patch / fix

  • Exim Exim 4.99.4
  • exim4 Debian 12 4.96-15+deb12u10
  • exim4 Debian 13 4.98.2-1+deb13u3
  • exim4 Debian 14 4.99.3-2

debian advisories DEBIAN-CVE-2026-48840

  • exim4 Ubuntu 22.04 LTS 4.95-4ubuntu2.9
  • exim4 Ubuntu 24.04 LTS 4.97-4ubuntu4.6
  • exim4 Ubuntu 25.10 4.98.2-1ubuntu2.3
  • exim4 Ubuntu 26.04 LTS 4.99.1-1ubuntu1.3
  • exim4 Ubuntu Pro 16.04 LTS 4.86.2-2ubuntu2.6+esm9
  • exim4 Ubuntu Pro 18.04 LTS 4.90.1-1ubuntu1.10+esm6
  • exim4 Ubuntu Pro 20.04 LTS 4.93-13ubuntu1.12+esm1

ubuntu advisories UBUNTU-CVE-2026-48840

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • exim Alpine 3.24, Alpine 3.23 4.98.4-r0

alpine advisories ALPINE-CVE-2026-48840

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48840 updated cvss 5.3

exim: Exim: Information disclosure via mishandled short payloads in proxy configurations

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected products

  • Exim Exim

Classification

Weakness
  • CWE-839 Numeric Range Comparison Without Minimum Check

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.