Description
The kill_something_info function in kernel/signal.c in the Linux kernel before 2.6.28 does not consider PID namespaces when processing signals directed to PID -1, which allows local users to bypass the intended namespace isolation, and send arbitrary signals to all processes in all namespaces, via a kill command.
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 5.0 | linux-2.6 | 2.6.26-15lenny2 | DSA-1800-1 |
| Debian 5.0 | user-mode-linux | 2.6.26-1um-2+15lenny2 | DSA-1800-1 |
| Debian 4.0 | linux-2.6.24 | 2.6.24-6~etchnhalf.8etch1 | DSA-1787-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat MRG 1 | kernel-rt +9 | 2.6.24.7-117.el5rt | RHSA-2009:1081 |
Advisories 3
- RHSA-2009:1081 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-1787-1 linux-2.6.24 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1800-1 linux-2.6 user-mode-linux - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
References
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=d25141a818383b3c3b09f065698c544a7a0ec6e7
- 35656 third-party-advisory
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.28
- 20090516 rPSA-2009-0084-1 kernel mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=496031
- kernel-killsomethinginfo-security-bypass(50386) vdb-entry
- [oss-security] 20090417 Re: CVE request: kernel: 'kill sig -1' must only apply to caller's PID namespace mailing-list
- 35120 third-party-advisory
- USN-793-1 vendor-advisory
- RHSA-2009:1081 vendor-advisory
- 34981 third-party-advisory
- DSA-1800 vendor-advisory
- [linux-kernel] 20080723 Re: [PATCH 1/2] signals: kill(-1) should only signal processes in the same namespace mailing-list
- 35343 third-party-advisory
- [oss-security] 20090421 Re: CVE request: kernel: 'kill sig -1' must only apply to caller's PID namespace mailing-list
- DSA-1787 vendor-advisory
- http://wiki.rpath.com/Advisories:rPSA-2009-0084
- [oss-security] 20090416 CVE request: kernel: 'kill sig -1' must only apply to caller's PID namespace mailing-list
- 35121 third-party-advisory