Description
Linux kernel before 2.6.18, when running on x86_64 systems, does not properly save or restore EFLAGS during a context switch, which allows local users to cause a denial of service (crash) by causing SYSENTER to set an NT flag, which can trigger a crash on the IRET of the next task.
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 4.0 | linux-2.6 | 2.6.18.dfsg.1-13etch4 | DSA-1381-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-92.1.18.el5 | RHSA-2008:0957 |
Advisories 2
- RHSA-2008:0957 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-1381-2 linux-2.6 Debian Security (DSA / DLA) · Mar 9, 2026
References
- 32485 third-party-advisory
- 24098 third-party-advisory
- http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commitdiff%3Bh=658fdbef66e5e9be79b457edc2cbbb3add840aa9
- RHSA-2008:0957 vendor-advisory
- 26994 third-party-advisory
- MDKSA-2007:171 vendor-advisory
- USN-416-1 vendor-advisory
- 26060 vdb-entry
- 26620 third-party-advisory
- DSA-1381 vendor-advisory
- http://www.kernel.org/pub/linux/kernel/v2.6/snapshots/patch-2.6.18-git13.log
- 20070615 rPSA-2007-0124-1 kernel xen mailing-list
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commitdiff%3Bh=658fdbef66e5e9be79b457edc2cbbb3add840aa9
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.18
- oval:org.mitre.oval:def:9554 vdb-entry signature
- 25691 third-party-advisory