Description
The vfprintf function in stdio-common/vfprintf.c in libc in GNU C Library (aka glibc) 2.12 and other versions does not properly calculate a buffer length, which allows context-dependent attackers to bypass the FORTIFY_SOURCE format-string protection mechanism and cause a denial of service (stack corruption and crash) via a format string that uses positional parameters and many format specifiers.
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 | 2.13-35 | — |
| Debian 13 | glibc | 2.13-35 | — |
| Debian 12 | glibc | 2.13-35 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | nscd +7 | 2.12-1.80.el6_3.3 | RHSA-2012:1098 |
| RHEL 6 | rhev-hypervisor6 | 6.3-20120815.0.el6_3 | RHSA-2012:1200 |
Advisories 2
- RHSA-2012:1200 Red Hat Security Advisory: rhev-hypervisor6 security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2012:1098 Red Hat Security Advisory: glibc security and bug fix update Red Hat Security Advisories (RHSA) · Jun 28, 2026
References
- RHSA-2012:1200 vendor-advisory
- https://sourceware.org/bugzilla/show_bug.cgi?id=12445
- https://bugzilla.redhat.com/show_bug.cgi?id=833703
- GLSA-201503-04 vendor-advisory
- RHSA-2012:1098 vendor-advisory
- USN-1589-1 vendor-advisory
- [oss-security] 20120711 Re: CVE request: glibc formatted printing vulnerabilities mailing-list