Description
transports/appendfile.c in Exim before 4.72, when a world-writable sticky-bit mail directory is used, does not verify the st_nlink field of mailbox files, which allows local users to cause a denial of service or possibly gain privileges by creating a hard link to another user's file.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | exim4 | 4.72-1 | — |
| Debian 13 | exim4 | 4.72-1 | — |
| Debian 12 | exim4 | 4.72-1 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | exim | 4.86.2-2.2 | openSUSE-SU-2024:10017-1 |
Advisories 1
- openSUSE-SU-2024:10017-1 exim-4.86.2-2.2 on GA media SUSE / openSUSE Security Updates · May 7, 2025
References
- 20100603 Multiple vulnerabilities in Exim mailing-list
- 40451 vdb-entry
- ADV-2010-1402 vdb-entry
- ADV-2011-0364 vdb-entry
- 43243 third-party-advisory
- http://bugs.exim.org/show_bug.cgi?id=988
- http://vcs.exim.org/viewvc/exim/exim-src/src/transports/appendfile.c?r1=1.24&r2=1.25
- 40019 third-party-advisory
- [exim-dev] 20100524 Security issues in exim4 local delivery mailing-list
- http://vcs.exim.org/viewvc/exim/exim-doc/doc-txt/ChangeLog?view=markup&pathrev=exim-4_72_RC2
- 40123 third-party-advisory
- 20100603 Multiple vulnerabilities in Exim mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=600093
- FEDORA-2010-9524 vendor-advisory
- SUSE-SR:2010:014 vendor-advisory
- USN-1060-1 vendor-advisory
- exim-mail-directory-priv-escalation(59043) vdb-entry
- FEDORA-2010-9506 vendor-advisory