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Fedora 43 Exim Important Info Disclosure CVE-2026

Linuxsecurity •LinuxSecurity Advisories • June 10, 2026

This is an update fixing a pre-authentication information disclosure (CVE-2026-48840).

* Mon Jun 1 2026 Jaroslav Škarvada - 4.99.4-1 - New version Resolves: rhbz#2483300 Resolves: CVE-2026-48840 * Mon May 18 2026 Jaroslav Škarvada - 4.99.3-1 - New version Resolves: rhbz#2476497

[ 1 ] Bug #2483300 - exim-4.99.4 is available [ 2 ] Bug #2484718 - CVE-2026-48840 exim: Exim: Information disclosure via mishandled short payloads in proxy configurations [fedora-all]

This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-71b1e9b455' at the command line. For more information, refer to the dnf documentation available at

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Critical Information Disclosure Vulnerability in Exim Affects Fedora 43 and 44 A pre-authentication information disclosure vulnerability (CVE-2026-48840) has been identified in Exim, affecting Fedora versions 43 and 44. The vulnerability allows attackers to exploit mishandled short payloads in proxy configurations, potentially leading to sensitive information exposure. The flaw was published on May 30, 2026, and has been addressed in the latest Exim version 4.99.4, released on June 1, 2026. Users are advised to update their systems using the 'dnf' update program to mitigate the risk. The vulnerability impacts all Fedora users running affected versions of Exim. The updates resolve the issues tracked under bug reports rhbz#2483300 and rhbz#2476497. As of now, there are no reports of active exploitation, but the nature of the vulnerability poses a significant risk. 2 sources 58

Extracted Entities

Fedora 43 Exim Important Info Disclosure CVE-2026

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Extracted Entities

Attack Types (1)

CVEs (1)

CWE Weaknesses (1)

Platforms (1)