Description
The (1) dshield.conf, (2) mail-buffered.conf, (3) mynetwatchman.conf, and (4) mynetwatchman.conf actions in action.d/ in Fail2ban before 0.8.5 allows local users to write to arbitrary files via a symlink attack on temporary files with predictable names, as demonstrated by /tmp/fail2ban-mail.txt.
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 | fail2ban | 0.8.4+svn20110323-1 | — |
| Debian 13 | fail2ban | 0.8.4+svn20110323-1 | — |
| Debian 12 | fail2ban | 0.8.4+svn20110323-1 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | fail2ban | 0.9.5-1.1 | openSUSE-SU-2024:10347-1 |
Advisories 1
- openSUSE-SU-2024:10347-1 SuSEfirewall2-fail2ban-0.9.5-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://github.com/fail2ban/fail2ban/blob/sdist/0.8.5/ChangeLog
- GLSA-201406-03 vendor-advisory
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=544232
- 58841 third-party-advisory