Medium severity · published May 30, 2026
CVE-2026-48840
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
5.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 18% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EX
Exim · Exim
4.88 before 4.99.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-48840
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-48840
Vendor Advisory
https://exim.org/static/doc/security/EXIM-Security-2026-05-19.1
Mailing List
https://www.openwall.com/lists/oss-security/2026/05/29/3
Mailing List
http://www.openwall.com/lists/oss-security/2026/05/29/3
lists.debian.org
https://lists.debian.org/debian-lts-announce/2026/06/msg00004.html
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