Description
The do_sigaltstack function in kernel/signal.c in Linux kernel 2.4 through 2.4.37 and 2.6 before 2.6.31-rc5, when running on 64-bit systems, does not clear certain padding bytes from a structure, which allows local users to obtain sensitive information from the kernel stack via the sigaltstack function.
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 | fai-kernels | 1.17+etch.24etch4 | DSA-1872-1 |
| Debian 4.0 | linux-2.6 | 2.6.18.dfsg.1-24etch4 | DSA-1872-1 |
| Debian 4.0 | linux-2.6.24 | 2.6.24-6~etchnhalf.9etch1 | DSA-1928-1 |
| Debian 4.0 | user-mode-linux | 2.6.18-1um-2etch.24etch4 | DSA-1872-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-164.el5 | RHSA-2009:1243 |
| RHEL 4 | kernel +10 | 2.6.9-89.0.11.EL | RHSA-2009:1438 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5.3 EUS | kernel +12 | 2.6.18-128.8.1.el5 | RHSA-2009:1466 |
| Red Hat MRG 1 | kernel-rt +9 | 2.6.24.7-132.el5rt | RHSA-2009:1239 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- Linux Kernel 2.6.31-rc5 - sigaltstack 4-Byte Stack Disclosure EDB-9352 · local · Aug 4, 2009 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 6
- RHSA-2009:1239 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2009:1243 Red Hat Security Advisory: Red Hat Enterprise Linux 5.4 kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2009:1438 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-1872-1 fai-kernels linux-2.6 user-mode-linux - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1928-1 linux-2.6.24 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- RHSA-2009:1466 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Nov 22, 2025
References
- [oss-security] 20090804 CVE request - kernel: information leak in sigaltstack mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=515392
- 37471 third-party-advisory
- USN-852-1 vendor-advisory
- RHSA-2009:1243 vendor-advisory
- 36759 third-party-advisory
- http://www.vmware.com/security/advisories/VMSA-2009-0016.html
- [oss-security] 20090826 Re: CVE request - kernel: information leak in sigaltstack mailing-list
- oval:org.mitre.oval:def:10637 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
- 36562 third-party-advisory
- FEDORA-2009-9044 vendor-advisory
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commitdiff%3Bh=0083fc2c50e6c5127c2802ad323adf8143ab7856
- oval:org.mitre.oval:def:8405 vdb-entry signature
- 9352 exploit
- 36501 third-party-advisory
- [oss-security] 20090805 Re: CVE request - kernel: information leak in sigaltstack mailing-list
- RHSA-2009:1438 vendor-advisory
- ADV-2009-3316 vdb-entry
- 37105 third-party-advisory
- 36136 third-party-advisory