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High 7.5Published Apr 30, 2026
CVE-2026-40684In 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.
Updated under an hour ago ()
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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.
- CVSS
- 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-684
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
exim exim exim:exim | before 4.99.2 | NVD |
References
- https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81patch
- https://exim.org/static/doc/security/CVE-2026-40684.txtbroken-link
- https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessmentvendor-advisory
- https://www.openwall.com/lists/oss-security/2026/04/30/21mailing-list, third-party-advisory
- http://www.openwall.com/lists/oss-security/2026/05/01/11
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.