CVE-2026-48840
CVE-2026-48840 is a medium-severity vulnerability in Exim with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-839.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- EPSS exploit prediction: 0% (18th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-33446
- Weakness: CWE-839
- Affected product: Exim
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-48840?
- CVE-2026-48840 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
- Is CVE-2026-48840 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-48840?
- CVE-2026-48840 affects Exim. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-48840?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-48840 have an EU (EUVD) identifier?
- Yes. CVE-2026-48840 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-33446.
- When was CVE-2026-48840 published?
- CVE-2026-48840 was published on 2026-05-30 and last updated on 2026-06-17.
References
- https://exim.org/static/doc/security/EXIM-Security-2026-05-19.1
- https://www.openwall.com/lists/oss-security/2026/05/29/3
- http://www.openwall.com/lists/oss-security/2026/05/29/3
- https://lists.debian.org/debian-lts-announce/2026/06/msg00004.html
Affected products (1)
- cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
More vulnerabilities in Exim
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- CVE-2022-37452 — Critical (CVSS 9.8): Exim before 4.95 has a heap-based buffer overflow for the alias list in host_name_lookup in host.c when…
- CVE-2020-28026 — Critical (CVSS 9.8): Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters, relevant in non-default configurations that enable…
Other CWE-839 vulnerabilities
- CVE-2023-0425 — High (CVSS 8.6): ABB is aware of vulnerabilities in the product versions listed below. An update is available that resolves the reported…
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Browse all CWE-839 vulnerabilities →
Threat intelligence
Threat-intel indicators referencing this CVE:
- 50.116.72.139 (ipv4-addr)
- 132.148.155.138 (ipv4-addr)
- 88.212.209.244 (ipv4-addr)
- 31.131.22.122 (ipv4-addr)
- 193.68.57.43 (ipv4-addr)
- 191.101.33.225 (ipv4-addr)
- 185.179.190.68 (ipv4-addr)
- 147.50.227.79 (ipv4-addr)