Description
The icmp_send function in net/ipv4/icmp.c in the Linux kernel before 2.6.25, when configured as a router with a REJECT route, does not properly manage the Protocol Independent Destination Cache (aka DST) in some situations involving transmission of an ICMP Host Unreachable message, which allows remote attackers to cause a denial of service (connectivity outage) by sending a large series of packets to many destination IP addresses within this REJECT route, related to an "rt_cache leak."
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.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-128.1.6.el5 | RHSA-2009:0326 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5.2 EUS | kernel +11 | 2.6.18-92.1.35.el5 | RHSA-2010:0079 |
Advisories 2
- RHSA-2010:0079 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2009:0326 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
References
- RHSA-2009:0326 vendor-advisory
- 37471 third-party-advisory
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=7c0ecc4c4f8fd90988aab8a95297b9c0038b6160
- http://www.vmware.com/security/advisories/VMSA-2009-0016.html
- 33758 third-party-advisory
- oval:org.mitre.oval:def:10215 vdb-entry signature
- 20091120 VMSA-2009-0016 VMware vCenter and ESX update release and vMA patch release address multiple security issue in third party components mailing-list
- oval:org.mitre.oval:def:7867 vdb-entry signature
- http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.25
- [oss-security] 20090311 CVE-2009-0778 kernel: rt_cache leak mailing-list
- 1021958 vdb-entry
- linux-kernel-rtcache-dos(49199) vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=485163
- ADV-2009-3316 vdb-entry
- 34084 vdb-entry