Description
The random number feature in Linux kernel 2.6 before 2.6.20.13, and 2.6.21.x before 2.6.21.4, (1) does not properly seed pools when there is no entropy, or (2) uses an incorrect cast when extracting entropy, which might cause the random number generator to provide the same values after reboots on systems without an entropy source.
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.1-13etch1 | DSA-1356-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +10 | 2.6.18-8.1.6.el5 | RHSA-2007:0376 |
Advisories 2
- RHSA-2007:0376 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1356-1 linux-2.6 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
References
- USN-470-1 vendor-advisory
- 1018248 vdb-entry
- 26664 third-party-advisory
- SUSE-SA:2007:051 vendor-advisory
- ADV-2007-2105 vdb-entry
- SUSE-SA:2007:043 vendor-advisory
- 24390 vdb-entry
- MDKSA-2007:171 vendor-advisory
- kernel-randomnumber-weak-security(34781) vdb-entry
- DSA-1356 vendor-advisory
- MDKSA-2007:216 vendor-advisory
- 26620 third-party-advisory
- USN-489-1 vendor-advisory
- MDKSA-2007:196 vendor-advisory
- [linux-kernel] 20070608 Linux 2.6.21.4 mailing-list
- 25961 third-party-advisory
- 37114 vdb-entry
- 25596 third-party-advisory
- RHSA-2007:0376 vendor-advisory
- USN-486-1 vendor-advisory
- 26450 third-party-advisory
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.21.4
- 25700 third-party-advisory
- [linux-kernel] 20070608 Linux 2.6.20.13 mailing-list
- oval:org.mitre.oval:def:9960 vdb-entry signature
- 26139 third-party-advisory
- 26133 third-party-advisory