Description
The ADDW macro in stdio-common/vfscanf.c in the GNU C Library (aka glibc or libc6) before 2.21 does not properly consider data-type size during a risk-management decision for use of the alloca function, which might allow context-dependent attackers to cause a denial of service (segmentation violation) or overwrite memory locations beyond the stack boundary via a long line containing wide characters that are improperly handled in a wscanf call.
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 | 2.19-15 | — |
| Debian 13 | glibc | 2.19-15 | — |
| Debian 12 | glibc | 2.19-15 | — |
| Debian 7 | eglibc | 2.13-38+deb7u8 | DSA-3169-1 |
| Debian 6.0 | eglibc | 2.11.3-4+deb6u5 | DLA-165-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | eglibc | 2.19-0ubuntu6.6 | USN-2519-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | nscd +7 | 2.17-105.el7 | RHSA-2015:2199 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7.1 EUS | nscd +7 | 2.17-79.ael7b_1 | RHSA-2015:2589 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | glibc | 2.24-2.3 | openSUSE-SU-2024:10154-1 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | dietlibc | 0.34-7 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | nscd +6 | 2.17-105.0.1.el7 | ELSA-2015-2199 |
Advisories 7
- RHSA-2015:2589 Red Hat Security Advisory: glibc security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- RHSA-2015:2199 Red Hat Security Advisory: glibc security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- USN-2519-1 eglibc, glibc vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3169-1 eglibc - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-165-1 eglibc - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10154-1 glibc-2.24-2.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2015-2199 Moderate: glibc security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 24, 2015
References
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- USN-2519-1 vendor-advisory
- https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Ba=commit%3Bh=5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06
- 72499 vdb-entry
- [oss-security] 20150203 Re: CVE request: heap buffer overflow in glibc swscanf mailing-list