Vulnerability in Exim
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002
Affected products
- Exim — versions 4.88
Weakness classification (CWE)
References
- exim.org/static/doc/security/EXIM-Security-2026-05-19.1 (Vendor Advisory)
- www.openwall.com/lists/oss-security/2026/05/29/3 (Mailing List, Third Party Advisory, Mitigation)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory, Mitigation)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2026-48840?
- CVE-2026-48840 is a medium-severity vulnerability in Exim, classified under CWE-839. CVSS score: 5.3/10. Published 2026-05-30.
- How severe is CVE-2026-48840?
- Medium severity. CVSS v3 base score is 5.3 out of 10.