Bug 2464258 (CVE-2026-40684) - CVE-2026-40684 Exim: Exim: Denial of Service due to malformed DNS data in PTR records on musl libc systems
Summary: CVE-2026-40684 Exim: Exim: Denial of Service due to malformed DNS data in PTR...
Keywords:
Status: NEW
Alias: CVE-2026-40684
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-30 22:02 UTC by OSIDB Bzimport
Modified: 2026-05-05 15:02 UTC (History)
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Description OSIDB Bzimport 2026-04-30 22:02:06 UTC 
In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.
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