🛡️ CVE-2026-48840 — exim

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

• Attack vector: Network — reachable from anywhere that can route to the service.
• Attack complexity: Low — the attack works reliably, with no preparation.
• Privileges required: None — an unauthenticated stranger can try it.
• User interaction: None — nobody has to be tricked into anything.
• Scope: Unchanged — the damage stays inside the vulnerable component.
• Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
• Integrity impact: None.
• Availability impact: None.

Weakness class

CVE-2026-48840 is classified as CWE-839: Numeric Range Comparison Without Minimum Check. The product checks a value to ensure that it is less than or equal to a maximum, but it does not also verify that the value is greater than or equal to the minimum.

Affected software

CVE-2026-48840 is recorded against 1 package.

• exim (from 4.88 up to 4.99.4)

Timeline and source

Published on 30 May 2026 and last revised on 22 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

exim.org
www.openwall.com
www.openwall.com
lists.debian.org

Other advisories for this package

exim has other advisories on record. If you are patching this one, these are worth checking on the same host:

• CVE-2026-66141 (7.4 High, published 24 Jul 2026)
• CVE-2026-66140 (8.4 High, published 24 Jul 2026)
• CLSA-2026-1779531839 (published 23 May 2026)
• CLSA-2026-1779531651 (published 23 May 2026)
• CLSA-2026-1778690918 (published 13 May 2026)
• CLSA-2026-1778690104 (published 13 May 2026)
• CVE-2026-45185 (9.8 Critical, published 12 May 2026)
• CLSA-2026-1778297730 (published 9 May 2026)

Same weakness in other software

These advisories are the same class of weakness (CWE-839: Numeric Range Comparison Without Minimum Check) in other software:

• CVE-2026-56968 (3.7 Low, published 23 Jun 2026)
• CVE-2023-0425 (8.6 High, published 7 Aug 2023)
• CVE-2023-22854 (7.5 High, published 13 Feb 2023)

CVE-2026-48840 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Affected Packages

References