Description
gcc 4.3.x does not generate a cld instruction while compiling functions used for string manipulation such as memcpy and memmove on x86 and i386, which can prevent the direction flag (DF) from being reset in violation of ABI conventions and cause data to be copied in the wrong direction during signal handling in the Linux kernel, which might allow context-dependent attackers to trigger memory corruption. NOTE: this issue was originally reported for CPU consumption in SBCL.
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 14 | glibc | 2.7-8 | — |
| Debian 13 | glibc | 2.7-8 | — |
| Debian 12 | glibc | 2.7-8 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | kernel +12 | 2.6.18-53.1.19.el5 | RHSA-2008:0233 |
| RHEL 4 | kernel +10 | 2.6.9-67.0.20.EL | RHSA-2008:0508 |
| RHEL 3 | kernel +8 | 2.4.21-57.EL | RHSA-2008:0211 |
Advisories 3
- RHSA-2008:0233 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2008:0508 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2008:0211 Red Hat Security Advisory: kernel security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
References
- 30962 third-party-advisory
- [gcc-patches] 20080307 Re: [PATCH, i386]: Emit cld instruction when stringops are used mailing-list
- [gcc-patches] 20080306 Re: [PATCH, i386]: Emit cld instruction when stringops are used mailing-list
- [gcc-patches] 20080306 Re: [PATCH, i386]: Emit cld instruction when stringops are used mailing-list
- http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=469058
- [linux-kernel] 20080305 Linux doesn't follow x86/x86-64 ABI wrt direction flag mailing-list
- 30850 third-party-advisory
- 30116 third-party-advisory
- RHSA-2008:0233 vendor-advisory
- 30110 third-party-advisory
- SUSE-SA:2008:031 vendor-advisory
- ADV-2008-2222 vdb-entry
- [git-commits-head] 20080307 x86: clear DF before calling signal handler mailing-list
- 29084 vdb-entry
- gcc-cld-dos(41340) vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=437312
- http://lwn.net/Articles/272048/#Comments
- RHSA-2008:0211 vendor-advisory
- oval:org.mitre.oval:def:11108 vdb-entry signature
- 30890 third-party-advisory
- RHSA-2008:0508 vendor-advisory
- [Security-announce] 20080728 VMSA-2008-00011 Updated ESX service console packages for Samba and vmnix mailing-list
- SUSE-SA:2008:030 vendor-advisory
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=e40cd10ccff3d9fbffd57b93780bee4b7b9bff51
- 31246 third-party-advisory
- [gcc-patches] 20080306 [PATCH, i386]: Emit cld instruction when stringops are used mailing-list
- 30818 third-party-advisory
- SUSE-SA:2008:032 vendor-advisory